The literature published at the beginning of the 1990s has reflected major developments in our understanding of the role of behavioral factors in the epidemiology and control of sexually transmitted diseases (STDs). First, the importance of overlap and interactions among sexual, substance use, and health behaviors; and among these behaviors and STDs, became clear. Second, for the first time, the prevalence and distribution of sexual behaviors in western European and North American populations were described. Third, the need to distinguish between population and individual level paradigms in the study of transmission dynamics and prevention of STDs was recognized. Finally, the approaches to the development and evaluation of behavioral interventions have also become increasingly more sophisticated.