Atlas of Men
I just received a book in the mail called Atlas of Men: Guide for Somatotyping the Adult Male at All Ages. It was published in 1954 and was written by William H. Sheldon. He is described by Wikipedia as "an American psychologist and numismatist who... tried to correlate body types with behavior, intelligence and social hierarchy through his Ivy League nude posture photos."
It sounds bizarre, and it is. Basically, all students in many Ivy League schools were being photographed nude for decades in the mid-20th century and were not being told what was happening with the images. Sheldon used the images to try to prove his theory that physical and mental attributes informed one another. This book is a collection of some of those photos. Included are more than 1,100 nude men, carefully documenting physical attributes.
As someone who tries to communicate through representations of the human figure this book is very interesting. Since I typically create the figures in my work from my imagination, it might be useful as an index of body types (unfortunately mostly only Caucasian male) that I can reference as I make decisions about the proportions of my figures.