This pathbreaking volume brings together a diverse body of sexual, behavioral, and social science research on bisexuality. Arguing for a clear, evidence-based definition of bisexuality and standardized measures for assessing sexual orientation, it spotlights challenges that need to be addressed toward attaining these goals.The book's deep trove of findings illuminates the experiences of bisexual men and women in key aspects of life, as well as common mental health issues in the face of stigma, prejudice, and outright denial from the heterosexual and homosexual communities.Throughout, contributors examine the paradoxical invisibility of bisexuality even as society and science have become more inclusive of lesbians and gay men, and emphasize the critical role of thoughtful, respectful support across societal and mental health domains.