God is Red - Vine Deloria Jr.

Attempts to demythologize American Indian religions while examining the 60s and 70s struggle of American Indian activists.  A mixed bag: certain very interesting insights into religion and sociological thought, but also some pretty extreme theories.

Darwin - Adrian Desmond and James Moore

A comprehensive biography. Really well done and given its 700+ page length really moves along at quite a good clip. Wonderfully socially situates what Darwin was dealing with and how he struggled to reconcile what his writings would mean for the world and himself.