Skin: A Natural History, by Nina G. Jablonski
As a cultural anthropologist, the author is fascinated by the history of skin. She writes about the many ways skin has evolved biologically and culturally. In my opinion, this book gives the best explanation for why there are so many different skin pigments, why we have different abilities to tan and freckle, and why some of us are more prone to sun damage and skin cancer than others. A great read for gaining insight into one of our most fascinating organs!