For decades, the field of gender, sex, and sexualities has been a focal point of increasing interest. This inquiry has been ignited by successive waves of dramatic social change, chief among them: the re-emergence of feminist movements in the U.S. and Europe in the late 1960s; the sustained (and increasingly successful) bids for legal, social, and religious acceptance of non-heterosexual sexualities in many parts of the world; and the burgeoning number of people (whether cisgendered, gender-variant, trans, or questioning) whose individual and collective experiences of gender and sexuality warrant deeper understanding and further progress toward a fuller realization of human potential and civil rights. In psychology, the intellectual project...