I just finished Perfectly Reasonable Deviations From The Beaten Track, a collection of letters written by Noble prize winner Richard Feynman and edited by his daughter, Michelle Feynman.

Feynman is one of the greatest, and one of the best known, scientists of the 20th century. I've been interested in him for many years, starting when I read his collection of anecdotes Surely You're Joking, Mr. Feynman and the follow-on, What Do You Care What Other People Think? If you are interested in reading his letters, I recommend reading the above two collections or one of his biographies first. The letter collection doesn't stand well on its own but it does provide some additional insight into his views.

Amazon Link: Perfectly Reasonable Deviations From The Beaten Track: The Letters Of Richard P. Feynman