I was immediately impressed with how friendly he was and how much he cared about students, just that we were just a friendly bunch in a way that I'd never experienced in England. Well, the very first afternoon when I walked into this freezing cold building and I met Bethe, the thing which I noticed first was extraordinary muddy boots he was wearing. It was one of these hot steamy days where the ground was very muddy and no professor in England would be seen in such muddy boots. And the other thing was that all the students called him Hans, and that was something completely new to me, I mean, even, I can't imagine calling even my best friend, Besicovitch, I never called him Abram and it just wouldn't have occurred to us to call a professor by his first name.

[Q] Nor Kemmer?

No, Kemmer was always Kemmer.

[Q] Dr Kemmer?

No, not Dr Kemmer. No - he was Kemmer, I think, but that's the way it was. I mean - family names. And, anyway, so Hans was very different and his whole style was different. He had this intense love of doing physics collectively. I mean that it wasn't really physics if you did by yourself, it was something you did with a group of people. And so I just loved it from the beginning and became very much a part of it right away. And then, of course, his way of work was actually quite unique, I mean if you compare Bethe with anybody else I knew. First of all, he had total command of the facts, that he absolutely just - you never needed to look up a number in a table because he knew them all. He knew all the energy levels of hydrogen and he knew the atomic weights of the different elements and the density of lead and gold and uranium, all these just physical quantities, he knew them all. In addition of course, he had an extraordinary ability to sit down and calculate and just simply go at it. He would have a problem, he would simply sit down and do it, and that's rather unique I think. I mean he went on calculating all day long whenever he wasn't interrupted, and he almost always was interrupted, but that didn't matter because he would get to page 352 in his stack of pages and then he would be interrupted by a student, and then as soon as the student went out of the door he'd go back to page 353, and he would just continue without a break. So he used his time with amazing efficiency. So he was able to do really hard calculations without spending too much time, just by working so efficiently. And he was, of course, also just extraordinarily reliable: if he said something, you could believe it. He was very careful about everything he said. So just a thoroughly solid person. Very different from Feynman, because Feynman was far more imaginative. I mean, one thing Bethe did not have was imagination; he never really invented anything, he just used the theories that were there to explain the facts, and he knew the facts and he knew the theories, so he just put them together; whereas Feynman was always inventing things and he didn't believe the theories that were taught in the textbooks, he had to make them up for himself, so he had a much harder time; but still, of course, in the end you need imagination too; I mean, both kinds of physicists are needed. But for me Hans was just ideal because what I needed was just guidance in doing some real calculations and as a guide Feynman would have been useless to me. In fact, he was not good with graduate students at all. He always said he didn't like graduate students and if he had a problem that would be of interest to a student he would do it himself, and that he just wasn't able to supply the kinds of problems that students needed because everything that he worked on was generally so imaginative and beyond the reach of students. So for me, it was far better that I was working with Bethe, but at the same time I could learn a hell of a lot from Feynman.