"In this textbook, Simon LeVay and Janice Baldwin aim to help students understand the diversity of human sexual expression as well as the diversity of perspectives from which sexuality can be studied. Well-known for its high-quality presentation of biological aspects of sexuality, the book also devotes rich coverage to the insights gained from cognitive science, social psychology, sociology, feminism, and cross-cultural studies, along with both moral and political discourse on sexual themes." For the Third Edition, the authors have made some organizational changes so that the book corresponds more closely to the sequence in which human sexuality is usually taught. The new edition provides up-to-date coverage of all topics, ranging from the newest developments in contraceptive technology to gay marriage in California. Still the leader in terms of its biological coverage, the Third Edition is more accessible to a broad range of students, thanks to simplified explanations of some complex biological issues.