Whether one defines sexual orientation as sexual behavior, self-identification, or attraction, sexual orientation is primarily about motivation. The same-sex marriage debate is part of a broader discussion about sexual orientation that we are having as a society. Many of the issues have or should be addressed by psychology and related fields, yet this literature is not yet well-known. Thus, the goal of this volume is to provide a forum for leading scholars to share their work on a variety of topics including the “coming out” experience, same-sex families, hate crimes and bias, and psychobiological underpinning of sexual orientation. Because gays, lesbians, bisexuals and their families live with an evolving legal status for their civing rights and protections, this volume also examines the topic from a legal perspective.