"Here is a fresh and readable solution to a major Darwinian puzzle. Homosexual acts do not lead to reproduction, which to Darwin was the major shaper of a species, yet male homosexuals appear in virtually every society--ancient, traditional and modern. The Puzzle describes homosexual life as it exists in the U.S. and in a number of other cultures, drawing upon field work, surveys, clinical work, and the writings of gay men themselves. The author's by-product theory is backed by evidence from anthropology, laboratory biology, and experimental psychology. In an Epilogue, the author discusses some practical issues, social and psychological, related to homosexuality"--