The Male Brain, by psychiatrist Louann Brizendine, M.D., details-- from the cradle to "the gray"-- the biological, psychological, and emotional drives that make us men.
I found this an exciting and interesting book to read (and you're talking to a guy who's mostly into magazines [they're more concise]). I saw myself and even my own father in some of the stories and explanations presented in this brisk read that maps the complexities of and misunderstandings about male development above the neck.
The book looks thick but what you're interested in comprises only 135 pages; the rest is notes, references, and the index. Brizendine's first book was The Female Brain. I haven't read that one but you're welcome to do so and slip me the CliffsNotes.