Not that Friedman needed such aid. He was an Esquire reporter researching a story on the burgeoning 1996 erection industry. "I had heard that drug companies had isolated substances that could give a man an erection on demand," Friedman explains in an e-mail. "To do a thorough research job, I had to try them myself."

Friedman took his eternal boner home. The damn thing wouldn't go down. Friedman stuck his hand in a bag of ice. No go. He lightly slapped his joystick. Still hard. He went to his TV and turned on the Home Shopping Channel and tried to bore himself limp. "Still hard as a rock," he remembers. It was then that Friedman had his eureka moment. His penis might as well have wiggled to get his attention and started speaking: "David, David, Dave! You are looking at the latest chapter in a really old story, maybe the greatest story never told: the story of man's relationship with his penis."

Friedman realized that, since Adam, a guy's most complex relationship was not with his parents or his lovers or his boss. It was with his prick. David M. Friedman knew he had to write a cultural history of the penis.

When Friedman's tool finally tuckered and fell, he went to work. His research took him to strange places, such as the Mutter Museum, a medical museum in Philadelphia. There, the curator, Gretchen Worden, showed Friedman her private collection of preserved animal phalli and other anatomical curiosities related to genitalia.

"Not for the fainthearted, trust me," he reports. "I remember seeing a monstrously large stallion penis, which Gretchen had a few horse laughs over. And I also have a recollection of seeing a human scrotum roughly the size of a bowling ball. Gretchen, who's an extremely intelligent and ebullient woman in her 40s (I'm guessing), revels in this kind of stuff, yet never loses sight of the fact that hers is an authentic medical museum -- and not a freak show."