This volume brings together contributions on the study of sexual affairs in committed personal relationships. The editors enlisted colleagues with varied theoretical and methodological perspectives from Britain, the United States, and other countries. Together, their contributions provide a broad, cross-national perspective on affairs. Grounded in theoretical discussion, the chapters in this book introduce data collected by a broad range of methods, including attitude surveys, large statistical cohort studies, case studies, depth interviews, and group discussions. A number of contributors locate the theoretical discussion of affairs within the broader contemporary ordering of committed relationships, contrasting the liberating and empowering aspects of affairs with the damage they may inflict on society as a whole and on the lives of individuals and families. The themes of passion, transgression, secrecy, lies, betrayal, and gossip are common to a range of chapters throughout. The volume provides broad literature reviews and theoretical discussions concerning particular aspects of affairs, such as communication and jealousy. In addition, case studies are used for the more detailed exploration of heterosexual affairs and contemporary developments in gay male and lesbian relationships. The State of Affairs will be of interest to researchers, scholars, and students in social psychology; communication; sociology; family, social, and clinical psychology; and for practitioners in couple counseling.