I knew all the time I was going to get through the war. It was completely irrational, a silly idea, but I was not going to lie down and get myself killed. I was going to get out of it.

Once I even took the train to Utrecht, forty miles from Amsterdam, with my yellow star, this star which I still have. Why did I go? I just wanted to visit some friends. I was a little bit crazy, a little bit insane.

I spent every night until four in the morning on my dissertation, until I came to the point when I could not write another word, not even the next letter. I went to bed. Eight o'clock the next morning I was up writing again.

The rule of the game was never assume that anybody, however honorable, would be able to stand up under torture. If Mr. X, who knew where I was, was caught for some reason, I should move.

[Heisenberg's seminal 1925 paper initiating quantum mechanics marked] one of the great jumps—perhaps the greatest—in the development of twentieth century physics.

One of the absolute rules I learned in the war was, don't know anything you don't need to know, because if you ever get caught they will get it out of you.

A number of current theoretical explorations will turn out to be passing fancies...