Book excerpt: In his early thirties, Ethan Watters began to realize that none of his friends were following the paths of their parents. Instead of settling down in couples and starting families, they lived and vacationed in groups, worked together at businesses they'd started, and met every week for dinner. As he started to document this phenomenon, he encountered countless other "tribes," in cities all over the U.S. Watters explores why tribe members have embraced this structure and what kind of affection and stability they find there, and contends that the conventional wisdom painting Generation X as isolated, selfish slackers may hide an unexpected, much warmer picture.