Another lovely look into Feynman's life, this book is a collection of letters Feynman sent during his lifetime. Witty replies to friends and laypeople, humble (and sometimes annoyed!) comments about the Nobel Prize, encouraging answers to students and many different types of letter make for a very interesting and entertaining read. The letters are arranged according to different time periods, with major events explained at the beginning of some chapters and other contextual information lightly interspersed.
I'd still recommend first giving a shot to "Surely You're Joking Mr Feynman" as an initial glimpse into Feynman's life, but this is a very nice addition, and if you've enjoyed the other one you'll like this one too.