Copied from... you know... that other place...

I recently read Self-Made Man: One Woman's Journey into Manhood and Back, by Norah Vincent. Go now, and read it, I command you!
Norah Vincent, in order to answer some questions about the differences between men and women, managed to convincingly (and temporarily) transform herself from a butch woman into an effeminate young man and interacted with other men in a variety of situations: she took on jobs, dated, joined a bowling league, even participated in a men's therapy group. Her book not only describes the differences in male and female interactions, but attempts to explain the roots of those differences. Moreover, she addresses not only gender identity but identity in general, and how assigned identity affects our relationships.
Since the public library never seemed to have this book, and I really, really wanted to read it, I broke down and violated my moratorium on book buying and purchased a copy- a hardcover copy, even. Then I stayed up all night reading it. The author is a writer, not a psychologist, but she is intelligent, sensitive, insightful, and astute, and the book is absolutely engrossing.