I've read a few science non-fiction books, but 'In the Shadow of Man' by Jane Goodall really stands out. Maybe because it was written so well. In this book, Goodall isn't simply listing facts about Chimpanzees to you, but writing in such a personal way that you feel you are getting to know the chimpanzees themselves. And when finished the book you can really see the similarities between humans and our close 'cousins' the chimpanzees.
All in all, I truely enjoyed this book. Not only do you get a glimpse of the life of a chimpanzee, you also get a glimpse into what's it like to study them.