The Passing of a Great Historian of Science

I was saddened to read that one of the great historians of science, Martin J. Klein of Yale University, passed away yesterday at the age of 84. He was a very down to earth and generous man, and was gracious in offering advice for one of my books. The first volume (of a planned two volume set) of a biography he wrote about physicist Paul Ehrenfest is a classic. (He never completed the second volume because he it was becoming too depressing for him to dwell on Ehrenfest's tragic final years.) Klein was also instrumental in the Einstein papers project and was the first recipient of the Pais Prize for the History of Physics. I remember him as a kindly, gray-mustached figure who was almost always surrounded by adoring former students.