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.

[George] Uhlenbeck was a highly gifted physicist. One of his remarkable traits was he would read every issue of T%he Physical Review from cover to cover.

Deliberately or not, every author is of course present in every book he or she writes - even in a scientific text.

There is not a soul on Earth who can read the deluge of physics publications in its entirety. As a result, it is sad but true that physics has irretrievably fallen apart from a cohesive to a fragmented discipline. ... It was not that long ago that people were complaining about two cultures. If we only had it that good. today.

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.

To make a discovery is not necessarily the same as to understand a discovery. Not only Planck but also other physicists were intially at a loss as to what the proper context of the new postulate really was.