Why do testicles hang the way they do? Is there an adaptive function to the female orgasm? What does it feel like to want to kill yourself? Does “free will” really exist? And why is the penis shaped like that anyway?     In Why Is the Penis Shaped Like That?, the research psychologist and award-winning columnist Jesse Bering features more than thirty of his most popular essays from Scientific American and Slate, as well as two new pieces, that take readers on a bold and captivating journey through some of the most taboo issues related to evolution and human behavior. Exploring the history of cannibalism, the neurology of people who are sexually attracted to animals, the evolution of human body fluids, the science of homosexuality, and serious questions about life and death, Bering astutely covers a generous expanse of our kaleidoscope of quirks and origins.      With his characteristic irreverence and trademark cheekiness, Bering leaves no topic unturned or curiosity unexamined, and he does it all with an audaciously original voice. Whether you’re interested in the psychological history behind the many facets of sexual desire or the evolutionary patterns that have dictated our current mystique and phallic physique, Why Is the Penis Shaped Like That? is bound to create lively discussion and debate for years to come.