This book by renowned psychologist and sociologist I.S. Con is unique. It summarizes modern data on same-sex love not only from the standpoint of biology and medicine, but also from the point of view of social sciences and humanities and psychology. The author considers in detail various theories of homosexuality, the history and ethnography of same-sex relations among the peoples of the world, the psychological features of same-sex love and eroticism, the problems of same-sex marriage, etc.