Eugene Stanley interview

Physics of Scale Activities

Interview with H. Eugene Stanley, 11 February 2002

Interview recorded at Boston University, Boston, Massachusetts.
Interview conducted and recorded by PoS collaborators: Babak Ashrafi, Karl Hall, and Silvan S. Schweber.
Edited by Alberto A. Martínez and Silvan S. Schweber.

PoS

The historical problem that we are trying to understand is not only what transpired in the formulation of the theory of phase transitions and critical phenomena, but also to understand the relationships between communities of physicists, mainly those in high energy physics and condensed matter physics.

HES

I know a little of that. Actually, I went to almost all the important meetings. I was a graduate student from 1963 to 1967 at Harvard and a postdoc after that.

PoS

Tell us a little bit about your background even starting where you were born...

HES

I grew up all over the place. My father actually worked for DuPont during World War II on the A-bomb project, the Manhattan project, as a lowly chemist without anything more than a Bachelor's degree. I had seventeen addresses by the age of ten. When I got my own security clearance, all seventeen had to be listed, and it took a long time to get security clearance. That fact, the one reason I mention it, is that it colored very much my father's life because he was told that this was to stop [Adolph] Hitler who he wanted to stop very much. And when the bomb was dropped he was completely devastated because they told him that the bomb would only be a defensive weapon against Hitler, not an offensive weapon against Japan and certainly not dropped on people when it could have been dropped on an island or used in some other demonstration purpose. So, this basically changed his life in the sense that he didn't cooperate any more with the atomic weapons development. He didn't work on the H-bomb as he was asked to do etc. and that was it. So, I was raised politically in this somewhat strange atmosphere of distrust of authority, you might say, and not believing... And I went to Wesleyan as an undergraduate and Harvard as a graduate student in physics.

PoS

Where did you go to high school?

HES

A public high school near Philadelphia called West Chester. Not especially good or bad, but relevant only in the sense of a school that drew from the entire region and therefore had a big fraction of every conceivable group of type of person from farmers far away to blacks and hispanics in the city of West Chester itself, pretty broad... not in a very isolated way, not in the ivory tower way. But, I was interested in physics as many people are because it's what we do well, you know, bind math interests and the desire to understand what matters in the world if you have a big curiosity as many people do.

PoS

So you come to Wesleyan actually knowing you want to be a physics major?

HES

More or less, yes. I chose Wesleyan for physics mostly because I had a National Merit Scholarship. I could go anywhere I wanted. I almost went to Princeton and at the last minute feared that at Princeton I wouldn't get much attention from the big professors and I was very afraid of that... At that time when I graduated high school '58 there had just been published a book on antisemitism at Princeton and at their eating clubs. The whole snobbism of Princeton. I actually signed up to go to Princeton, paid my deposit and I cancelled.

PoS

What made you choose Wesleyan?

HES

Wesleyan because it had very good physics teaching facilities at that time in '58 and they have the undergraduate thesis requirement. They had very small classes and so forth, I would interact, at least wouldn't be drowning. And Westchester High School was sufficiently poor that there was no question that I would enter Princeton in, shall we say, in the lower half if not the lower quarter of class in terms of preparation. And which sent me to Wesleyan, but at least in Wesleyan the classes are small so I got a C in English the first semester because I didn't know what it meant to write an essay. I had to do that. I had to know what symbols were. My high school never taught any of that. Physics went better because it's easier but it was still hard, and Edwin Taylor, my physics professor, told me I should get out of physics, for sure get out of theoretical physics and maybe do some kind of experiment, just based on my performance in his honors class and maybe I should have, but I didn't, but it sticks in your mind many years later, 45 years later. I also was into some biology. So, the next big event was that I wanted to go to graduate school in biophysics and everyone in physics knew at that time knew one very successful person, [Max] Delbrueck, so I wrote to Delbrueck a letter at Caltech saying I want to come to Cal Tech and be in graduate school to study with him. And he wrote back: 'I will be on a sabbatical in Germany, but you're welcome to come to Germany as my only students, so you will get lots of attention." So, I applied for a Fulbright, got it and went to Germany for a year with the intention of continuing with him. However, this year in Germany was the solidifying event in my scientific career because I had a role model that I could more or less copy, although perhaps not all the time. I didn't always like what I saw at that time, but, as you know, over the years you realize that he did it right, and I was too intolerant then.

PoS

So, you didn't apply to graduate school when you were a senior?

HES

I think I applied only to the Fulbright. I must have applied to graduate school , because you don't find about a Fulbright until later. If I applied to graduate school I don't remember. The bottom line is after a year in Germany of doing biophysics I could have continued in biophysics research but Delbrueck himself said this is a dumb degree to get for interesting reasons, namely that that you learn a lot about several fields, like biology, chemistry, physics, but you don't learn enough about any one field to develop self-confidence and credentials. If you said "Particle physics" at Stonybrook , wow, this person knows particle physics, but if you said you did biological chemical physics at Stonybrook, I might wonder what you really know, but this was roughly his point. And so I applied to pure places that did physics.

PoS

In what way was he a role model for doing physics?

HES

First of all immense honesty. An emphasis on clarity of what you know, what you don't know. And an emphasis on, this sounds awful but it's true, and I copied them, emphasis on not reading but "doing" if you will. For example, when I arrived in Germany looking for physics background I said what can I read and he said: 'No, you shouldn't read, you work', and I said 'Well, can I read at night?' He wouldn't tell me, but of course you finally find some things to read. But if he would catch me during the day reading the book, he would scold me and say you should be working, you should be doing things, not reading.

PoS

This is roughly the time when he wrote his famous essay on being a physicist doing biology?

HES

That was later than that, this was 1962. He was 58 at the time. But a very young 58. With a new baby and so on. Also, he's a very impatient person for, shall we say, clarity. I haven't done this yet, but he's quite known for just opening up a paper during a colloquium when it became unclear. After a few attempts to make it clear, you ask: 'Professor what do you mean, what do you mean,' instead of just giving up. Yes we all do often, we just give up at a colloquium. Most of us daydream, or pull out our agenda and write a list of things that we have to do. But he would just open the newspaper.

PoS

Coming back to Delbrueck. What did you do? What did you do that year?

HES

Not as much as I should have, but I did a lot of experiments, and I learned that I didn't really enjoy experiments that much. It was a little tedious. I really would rather read basically, despite being told not to, and understand what I was doing, so then I came to Harvard, I came there when Delbrueck told me to work for Wally Gilbert. I knocked on his door and I arrived in September '63 and said who I was and he said 'Yeah I know you are coming into this work, but I don't think you want to do biology or biophysics and I said 'Why not?' Before he could answer, the phone rang and he talks a little to somebody about arithmetic, you know, how to do percentages and stuff like that and he hung up and he said 'Do you like math?' and I said 'Yeah, of course.' He said, then you're really not going to like biology because that was my technician and I spend every day, certain number of hours, just explaining how to do percentages and do these things, you know, but he's gotta do it right or else the experiment is wrong and there is no math in biology and it's all experiment. So it sort of scared me away. And as I needed money for the first summer, I took a job at Lincoln Lab which at that time was a very, very vibrant place in what is now called condensed matter physics. It had Milly Dresselhaus, Gene Dresselhaus, Irwin Shapiro, and some of the names you probably know, and I was again the only student there so I got a huge amount of attention and I realized that I liked physics more that biology, so I just did a PhD in physics. Nominally with [John] Van Vleck but in practice, basically at Lincoln Lab. We had huge amounts of attention there, lots of mentoring.

PoS

Could you tell us a little bit more about what courses you took when you came to Harvard? What do you remember?

HES

I made a lot of mistakes when I came because I lost a year on the Fulbright. I thought I could place out of some courses and Harvard is a little bit relaxed on how they do things. They don't force you to do much, and therefore I did not take a course in say quantum mechanics, because I went to take the [Julian] Schwinger's lecture on field theory and [Sidney] Coleman taught it also, and the bottom line is that I created holes in my physics education which I then was never able to fill because I never had the time to sort of go back and learn a lot of these things. So, it's made me a good teacher, because I tell students not to do this. It leaves you insecure, but I did do well in graduate school, well enough to get a Mellon Fellowship at Berkeley, assistant professorship at MIT, but not by virtue of will and head, but by virtue of the good luck of research, in fact. Critical phenomena was just opening up, and it was possible for new kids on the block like me to stumble onto nice discoveries and that's what made my career.

PoS

What steered you in that direction? What courses, what stimulation?

HES

Nothing, nothing special, it was just an exciting new field...

PoS

You took courses with Paul Martin?

HES

Yeah. Did I take it for credit or for audit is a good question.

PoS

Doesn't matter.

HES

Martin just at that time was, for sure, the worst teacher imaginable, because he couldn't finish a sentence. He would start but never finish so everyone knew he was brilliant and you had to understand it, but it was almost impossible to understand it. I think I only audited that course. It was an advanced course, really advanced. [Roy] Glauber taught me the stuff, that I know. Glauber was the opposite so clear that he made it sound trivial which of couse it's not. Statistical physics is still for me the most difficult physics of all of physics to understand. And when I have to teach it I go crazy.

PoS

But you say it was Lincoln Labs that drew your attention in that direction.

HES

Perhaps, yeah, although to be honest, at Lincoln Labs I was not doing this so much. I could show you exactly what I did and then it was called many body theory, and Green's functions.

PoS

With Gene Dresselhaus?

HES

No, with Tom Kaplan ... I gave, I remember, several lectures on Green's functions, but the trouble for me with that is that it had ... already hit its peak, ... The obvious things were done and I didn't have any very good ideas of what to do.

PoS

These are presumably the temperature dependent Green's functions...

HES

Yeah.

PoS

... and from where did you learn those?

HES

The Kadanoff-Baym book.

PoS

Did you know of Dzyaloshinskii yet?

HES

Personally, I don't. Of course, I know his work.

PoS

Well, the textbook of Alexei Abrikosov, Lev P. Gorkov and Igor Dzyaloshinskii had been translated into English in 1963.

HES

Then I would've noted its publication, but I don't remember reading it.

PoS

But it's primarily Gordon Baym and Leo Kadanoff that taught you these methods... Were they at Harvard with you?

HES

Kadanoff was a whiz kid, he went out of school very, very fast.

If I'm not mistaken Kadanoff finished about 1960.

PoS

So in the summer of 1964 you actually go to Lincoln lab.

HES

That's right

PoS

And what did you tell them?

HES

I told them what I couldn't figure out about Green's function, but it was clear to me that it was a dead end for me. I have always felt somewhat unsatisfied... perhaps because I'm partly insecure about my own abilities. I felt that the only way I'm ever gonna make it is to do something in some new field that nobody has done much in. There are either plums to be plucked or not. There are always plums to be plucked but usually there are more likely to be plums that I can reach on the tree in a new field than on those in mature fields. I didn't much like Green's functions.

PoS

But I mean, how did you pick your thesis topic?

HES

Well, it's all sort of coming back. It's amazing how your memory can distort past events so easily... How I picked a thesis topic is a good question. ... There were a zillion conferences and things on critical phenomena in that period and all kinds of interesting ideas were being floated around and it was very alive and energetic. It was a nice mix of experiments, -- this is very important for your history -- and in my opinion the field developed for a lot of reasons, but one that's often overlooked is that there was a very strong mix of theory and experiment

PoS

Did you have much interaction with George Benedek at the time?

HES

Yes, yes.

PoS

He was still at Harvard.

HES

I guess, I met him only in conferences... and I didn't go to his lab. I didn't have interaction with anybody, except the Lincoln Lab staff, especially Tom Kaplan.

PoS

Who were your friends among the graduate students at that time? Who do you remember most?

HES

To be very blunt most of them have dropped out. I'm not saying it to brag, I am saying that partly in order to criticize Harvard, although it's a natural interpretation of the fact that graduate students got no offices, you saw all the professors by appointment .... The case is often more than that. So, the people at Harvard that I can remember knowing was Barry McCoy, he was in the same class . McCoy was and has been very successful... and that's about it.

PoS

Did you ever have any interaction with T. T. Wu?

HES

Only because he was McCoy's advisor.

PoS

Before we leave Lincoln Labs can you tell us about Tom Kaplan ?

HES

Sure yeah in fact you can interview him, he is very alive and vibrant. He can give you very good stories and more accurate than mine. Kaplan was a student of Herb Callen at Penn who in turn was a student of Lazlo Tisza who in turn was a student of Edward Teller, who was friend of Leo Szilard who was student of Einstein, who in turn knew [Ludwig] Boltzmann. Kaplan after his PhD at Penn went to work at Lincoln lab because it was an exciting place. And his main claim to fame was the discovery of a spiral ordering as the actual ordered state, not a spin order. Just as there is ferromagnetism and there is antiferromagnetism there is also a set of compounds, not too huge, for which the ordering is not one of what I said, but it's actually a spiraling law. Spiraling means that if I'm a spin I point to, say, the North Star, and you point 10 degrees to the left of the North Star, and you 20 degrees and so forth so 36 spins down the line we've come around the full circle again. And he made this discovery independent of two other people. Jacques Villain a very big name. But, he was a very powerful influence because he is also very clear. It's the tendency of physicists , as you know, is to sort of say the most obvious when they don't understand. They don't want to talk about it so it must be obvious, or it's just that it must be obvious. He was very good to work with, as a student because he never sort of put you down. Most students thought that most professors put them down a big fraction of the time.

PoS

Where was your introduction to things like Heisenberg models, Ising models etc.?

HES

At Lincoln Lab. John van Vleck taught a very nice course in magnetism, which I took. And taught it in a way which is also valuable to historians. His way of teaching is a way that I've never been able to quite teach but I've always wanted to. He would come in as if he were totally unprepared, you know and everyone would wonder whether he was or not, and he would say 'Today we're supposed to talk about paramagnetism and does anybody know about paramagnetism?' And we would say, 'yeah the spins don't interact.' And he would say 'When there is nothing you can say, I guess' or something, and then he would sort of say 'Well, you ought to be able to calculate how even if they don't interact they must respond to magnetic fields so I guess the one interesting thing would be how the magnetization responds to the magnetic field.' And we would say 'Hurry up, hurry up, hurry up', and he would go very, very slowly but he would , sort of, teach us how he approached science in that way. And at the end of the lecture you wouldn't have much in your notebook, but... he would have just explained perfectly... He taught a lot.

PoS

Wendell Furry.

HES

No he then ... he didn't teach graduate courses. And he was regarded as a man who had fallen afoul of the [Joseph] McCarthy people...

PoS

This is now almost ten years later.

HES

Yeah, and there was a lot of pity for him on a personal level...

PoS

And didn't you take anything with Sidney Coleman?

HES

Yeah, yeah I did take Coleman's course and that's why I got out of field theory, I think that when I entered Harvard I wanted to be a Schwinger student.... In Germany I dreamed of Schwinger: he was a big monstrous guy but when I met him he was a short guy. So I took a reading course like so many students did the first semester, and had the exactly the same experience that everyone had of meeting him: once in the fall you saw him to sign a card and at which time he told me to come back in January at the end of the semester with the term paper. Which I did. ... So that didn't help me make a decision, but Coleman's course did, because Coleman's course was very hard.

PoS

All field theory.

HES

Field theory, from a thick set of notes of his. A very difficult a very, very nice book, a very thick book and a lot more details, but Coleman, was a very tough person. In particular, he gave a take home exam which was so tough that no one in the entire class could do it and you had 4-5 days. Except, the day before it was due Jeff Mandula said 'I can solve it,' and everyone didn't know if he was bluffing but he could, so Jeff got an A, the rest of us got B's and, basically, the message from Coleman was you shouldn't think of field theory if you couldn't get an A. Jeff Mandula could think of it if he wanted to and most of us really should not and I took that lesson to heart. I also sat in on Schwinger's course, I don't think I took it for a grade, but I was there the day he got the Nobel Prize. And I was the person who ran out to the liquor store and bought the champagne. So, he came in his characteristic way, four to five minutes late. There was the bottle of champagne sitting on the table and, of course, the class wanted to know what he would do about it, would he actually smile and to signify that life had changed suddenly that morning. He stopped talking, very clearly looked at the class and said 'Thank you.' So, he at least acknowledged that it was there, but he didn't start to tell stories about his childhood or how he made the things for which he had just been given the Nobel Prize which most of us didn't really know because it was the beginning of the semester, October...

PoS

Can we come back to Kaplan?

HES

Yeah.

PoS

Was it unusual to actually pick someone at the Lincoln Lab?

HES

Moderately unusual, yes, but Harvard has a policy... they were delighted if you did your thesis elsewhere. Most schools reluctantly agree to it.

PoS

So he was officially your thesis advisor?

HES

Officially it was van Vleck.

PoS

But Kaplan signed.

HES

He didn't even sign. He was at least invited to the thesis due to the fact that he had signified that the work was good. Van Vleck also had to make his own evaluation... They paid me at Lincoln Lab, actually a supplement to my NSF fellowship. But the main reason to be at Lincoln Lab was just to have this wonderful ambience. There weren't parties every weekend, but it was almost that. And if was definitely the feeling the doors were always open, you could benefit from anybody. And it was a strongly interactive group and that has influenced my professional career. I have had a lot of PhD students, roughly 80, and I worked with roughly 100 postdocs, almost forcing them to be creative ... hopefully not all of them think of being forced, but it required interacting strongly. And often it's very painful... to get along so well after a certain period of time.

PoS

Can you tell us a little about what you did with Kaplan ?

HES

I certainly can tell you. The Heisenberg model as you said was a model that was studied a lot at that time because it described magnetic materials, but it also had a critical point that could be probed experimentally. By computation or theory you could determine its properties near the critical point. There was a theoretical method which at that time was called 'high temperature expansions' which almost took you close to the critical point.... People liked to joke about it as a brute force method. I called it something slightly different. I called it the method of exact enumeration where one would actually enumerate all the paths of a given length by which two spins can be correlated, and length at the time was limited to sort of 8 intervening spins, not very many, but the important thing is that if you enumerated every path then the progression of how properties changed as you went from paths of length two to three, three to four, four to five, was a rapidly convergent sequence and it displayed a trend that could be extrapolated to infinity and give highly accurate numbers for critical exponents. Exponents were the thing at that time because it was what experimentalists measured. So I became, because what I did at that time were the best calculations on that model, I became an "expert"... You know, I could go at the meetings and people cared about what I did and I would talk to experimentalists and they'd care, and it was all within the range of my abilities because this is, as I said, a brute force method, more or less. I had to use a computer and the use of computers was in '63, '64, '65 not very prevalent sufficient so I knew what many people didn't know how to do, how to work with a computer, and Lincoln Lab had a computer that I could use on nights and weekends.

PoS

And that was in fact the place where you picked up the expertise?

HES

Correct, correct, I had the whole Lincoln Lab computers.

PoS

Punch cards or anything like that.

HES

Punch cards and sometimes paper tapes, but I literally had the whole computer for myself. It was slow of course, but it did the bookkeeping. And the ideas were simple, so the bookkeeping was more or less straightforward and so I excelled not by virtue of some genius on my part, but just being lucky at the right place. And willing to do a problem that probably some graduate students wouldn't, because they'd rather do something more esoteric sounding. But, the Heisenberg model work was successful particularly because of the fact that one day I thought of looking in two dimensions , as opposed to three dimensions where the experiments were, and no one, almost no one... looked at two dimensions. And when I found the evidence on this method which was the accepted method, the method of high temperature expansions which was as convincing in two dimensions for a transition as in three, this was a very exciting piece of work, so exciting that I wanted to publish it immediately myself without my advisor, without telling him that. But I will always remember when he took me aside a week later and said 'You know, it's true, it's your idea, but we worked together all this time, you wouldn't be where you were, and so on and so on,' and he said 'You're not gonna get this written up an published without some help, and I would like to collaborate with you,' And so I was full of shame instead, of course, of course, of course. And now as an advisor I've been in that position. I've been in that position more than once in my life and I know how delicate intellectual property like that can be. But, I was very excited about that piece of work, that began a part of my life which was very, very important for the field and for myself, because there were two problems. The theorists didn't want to accept this because there were some arguments from the spin-wave theory that two dimensional magnets should not exhibit critical phenomena. With Kaplan's help we were able to show that those arguments only meant you could not have a spontaneous magnetization, that means that the net number of up spins when you turned off the field, didn't go to zero as it does above the critical point. So, that old argument only applied to that, and furthermore that old argument wasn't even rigorous. [David] Mermin, [Herbert] Wagner and [Pierre] Hohenberg supplied the rigor shortly thereafter, but it was still ruling out a magnetization. But the transition that we uncovered was a transition with a divergent susceptibility which has not to do with the magnetization, but the fluctuations of the magnetization and what a quantity does or what its fluctuations do have almost nothing to do with each other. So, we argued that the fluctuations should diverge, the susceptibility should diverge, the magnetization should always remain zero and that was a very hard thing to swallow by theorists. My paper was rejected. Vociferously rejected, but then it was accepted by [Freeman] Dyson who I had met at Brandeis summer school.

PoS

When Dyson talked about the stability of matter?

HES

Cooperative Phenomena near Phase Transitions

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PoS

An aside, when did you first plow through or really come to terms with Lars Onsager's model?

HES

Never. When I wrote the book I had to learn enough about the two dimensional Ising model to decide whether to give a solution or not, and there's an appendix which gives an interesting Russian graphical solution that at least has some physics to it. I was never a fan of monster formalism, and I've become even less of a fan now, so I often tell my students... [Lars] Onsager and [Bruria] Kaufmann's famous paper, of course, is very important in the history of physics, no question, but in terms of what a student learns by spending a week or two weeks or something , going through it and learning how to do it all is probably a less good use of time than something else, because at the end of the day you finish the solution you don't sort of understand it. I never became, I was never a fan of doing really heavy, you know, sledge hammer math.

PoS

Another aside, since we didn't pick it up when you were at Wesleyan... the work that you did there it was again purely theoretical?

HES

At Wesleyan I did a thesis in atomic physics.

PoS

On electron capture with Thomas Green? And it's theoretical?

HES

100% theory and... I think I ultimately published the paper with his name, deservedly, first because I was an undergraduate, he was more or less telling me what to do when I did it.

PoS

Do you remember why it was that you came to the Heisenberg problem with Kaplan , what was at issue?

HES

Good question, no I don't remember exactly. Maybe, he'll remember, but roughly what I guess is that there wasn't any defining event. If you're in a research group of solid state physicists, the Heisenberg model is sort of the number one model, and the critical point is the number one puzzle that young people were interested in. And I was young and I could read all the papers and learn all the facts. I became a local expert in the sense that I knew the newest paper the way my students now know what came out last week and I don't because I am behind.

PoS

So, in terms of critical issues, you knew the work of T. D. Lee and C. N. Yang and all of the current interest in thermodynamic limits? For what potentials and what statistics it exists

HES

Yeah, again heavy formalism. Yeah, of course I knew of their work, in fact I even own Yang's University of Washington dittoed lectures that Frank Black made, do you know about them? Most people don't know they exist. Michael Fisher is waiting for me to find my copy and share it with him.

PoS

Oh, well he can come to our website and look at them.

HES

Oh this very nice. Very very nice, ...

PoS

Would you happen to have your notes on Van Vleck's course on magnetism?

HES

I have lecture notes only, yes, sure, of course.

PoS

Oh, you do? Wow.

HES

I have all my lecture notes. I am really a terrible pack rat. As I told you when you called.

PoS

That's great, that's wonderful.

You went to Brandeis summer school and earlier on you said that one of your main ways of learning about this topic were these conferences and summer schools.

HES

Mainly, I said that I enjoy just narrowly being in the thick of things. In the thick of things, you know, me being able to be at some of the talks about great ideas; to be able occasionally to talk to these people. I like that, I like that excitement, so for example, Brandeis summer school was an ideal thing because I knew Kadanoff and Dyson there very well and also Robert Brout. He came to my house for dinner, so obviously I must have wanted to meet them more or I wouldn't have invited them for dinner. And I guess that was exciting, I mean, the hillbilly from Oklahoma meets the great, you know, Freeman Dyson or something it was a big high, you know a big high, like a kid who meets a rock star or something. I knew there was some element of that, 'cause I always was in awe of these very special physicists...

... and Kadanoff, I met him... And I have kept relationships with all these people and I speak with them now.

PoS

And eventually that was part of the idea when you were at MIT: to run a summer school in the '70s?

HES

Partly, but the main reason was money. MIT refused to give you the third month of salary no matter how many grants you had, but if you taught in the summer school, if you could create one of those courses you could then get it. And I had a very lousy salary. 12,500 dollars for nine months. And it also had a budget to bring people, and this was very nice, Summer schools were nice, ... nice for the people who came together.

PoS

Let's go back to 1965, you were aware at that stage of the NBS conference.

HES

I wasn't there though.

PoS

You weren't there?

HES

Nope, but I own 4 or 5 copies of the proceedings 'cause they were free, you just write to NBS, and I used to get them for my friends just by writing for more. And particularly, maybe you know, they have all the discussion at the end of every talk...

PoS

Did you really study that?

HES

Yeah, especially the discussion...

PoS

And who had told you about the conference?

HES

Everybody knew. . . . Big excitement... I'm guessing it was 1964, not 1965.