Vintage, Toronto, 2000, 1^st pr thus.  ISBN 0-679-31007-X.  Trade soft cover, 392 pages including Sources, Acknowledgments, and Index.  Unread remaindered copy, bit of soil on bottom edge.  ‘Can open eroticism between more than two consenting adults be considered natural sexual behavior?  Is it possible to experience sex with other partners while happily ensconced in an emotionally monogamous marriage?  Is swinging merely an invention of sexually permissive modern times? … swinging has roots that go back thousands of years and seem to serve a variety of social and biological purposes, some of which we have only just begun to understand.  Controversial and unique, The Lifestyle offers a riveting look at what it means to be part of a growing subculture of mainstream adults who are changing the rules of sexual behavior for pair-bonded humans.  Or are they?’ (from rear wrap)