The capacity to be attracted, and attractive, to people of both sexes is something we take for granted in the famous and infamous (rock stars and other celebrities); in the unfamous we tend to ignore it or to dismiss it as confusion or lack of self-knowledge.

Yet bisexuality shows up everywhere once we open our eyes - in our daily lives, in our childhoods, in books, movies, art, and popular culture. As part of our contemporary obsession with categories and identities, we use marriage and other institutions, homosexual as well as heterosexual, to pigeonhole sexuality. But why should we? We live long sexual lives, in the sense that between birth and death we form many intense and varied personal attachments.

We tend to select a few of those attachments and derive from them a label, "straight" or "gay," for our "sexual identity." The rest - an adolescent "crush," for example, or the passion a favorite teacher inspired - we write off as "phases" or footnotes. But, as Marjorie Garber reveals, this pruning away of our sexual lives cuts us off from many deep and important feelings.

1. Garber argues that erotic life is, by nature, politically incorrect and unpredictable. This unpredictability locates bisexuality not between heterosexuality and homosexuality but beyond them. Gathering evidence from art, literature, film, pop culture, advertising, science, and psychology, Garber documents how, both for cultures and for individuals, circumstance, accident, and inclination produce a rich and complicated history of emotion and experience over time.