George Uhlenbeck recalls his encounter with Enrico Fermi: After my [M.Sc. exam in Leiden, in the Summer of 1923], Ehrenfest said that I should look up Fermi. He gave me a letter and also a series of questions. That was typically Ehrenfest. This was in connection with the paper of Fermi on the proof of the ergodic theorem... Ehrenfest was so impressed by that paper, he wrote a paper himself, which is also in the Collected Works, and sent a copy of that with some questions. I was supposed to look up Fermi, who was then what they call "littera docente" in Italy. And of course in this whole physics building, I still don't know precisely where it is. Anyway, I looked him up, of course, and Fermi was clearly very alone. He had two people who were at least about his own age, and with whom he could talk. Those two were Pontremoli and the other was the man who is now professor at Torino, Persico. I talked a lot with Fermi. I remember that he walked home with me and talked, and I have, even, the memory that he talked with me about the Fermi statistics. And so that is where I really learned to know Fermi. I told him about Leiden very much, and that, I am sure, made him decide to use the half a year of his fellowship that he still had. That was, of course, an international Rockefeller fellowship, of which he spent one half year in Gottingen and had quit. He never said [why he quit Gottingen]. I know only indirectly that he was not happy there. And then we said we should have a little seminar, because then I talked about the Ehrenfest colloquium and how fine it was. But I was of course, compared to him, a complete beginner. He was younger than I was, but he was in a sense a wonder child, like Pauli. At Pisa he wrote about general relativity and what not. He knew everything. And as I said, I think this must have been before he began to tell me something about these electrons in a harmonic oscillator field, and then, of the exclusion principle. I didn't quite understand. I may have been mistaken, maybe it was later. But it must be about that time though. Anyway, we had then a little seminar, with Pontremoli, Persico, and me, in this old building. Of course Fermi always talked. It was really a little lecture that he gave us. And what we talked on was the classical perturbation theory, three-body problem, analytical mechanics, all applied to the quantum theory. You see, all these things which one now finds in the first volume of Born. Fermi knew everything, and he talked about these things... This was the topic of our seminar. He was so much ahead of all three of us, that he was the one who talked all the time. Interview with Dr. George Uhlenbeck By Thomas S. Kuhn, April 5, 1962 http://www.aip.org/history/ohilist/4922_3.html