I just finished reading Bonobo Handshake: a memoir of love and adventure in the Congo, by Vanessa Woods. I thoroughly enjoyed it. It's reminiscent of books by Dian Fossey and Jane Goodall only it's set mostly in the Congo and is about bonobos. Not only did I learn about the bonobos (closely related to chimps but they live in matriarchal societies and they prefer to make love rather than war) but I also gained some knowledge of the history of the region. The latter was particularly interesting since I was in Rwanda a year ago and the two countries share a border, some ethnic groups and some political history.
Otherwise I've read some books by Michael Connelly and Lee Child which are always bestsellers.