Public health has a legacy of neglect regarding social and behavioral research. Too often, prompted by technical and scientific progress, we have ignored- even marginalized-the vital "human element" in health thinking and prac- tice. Thus, for example, while family planning programs focused on providing a choice among safe and effective contraceptive methods (a supremely worthy goal), the central issue of sexuality and sexual behavior was generally neglected. Similarly, the enormous and important efforts to develop rapid and reliable diagnostic and treatment methods for sexually transmitted diseases helped divert attention away from the crucial issues of sexual practice. In short, we seem to have difficulty addressing the fundamental behaviors-including sex, drug taking and other intoxications, and violence-that are central to the major causes of preventable morbidity, disability, and premature mortality in the world today. Our collective reluctance to examine and understand ourselves is also expressed in the oft-repeated pipedream that scientific progress will "take care of" the HIV / AIDS pandemic by delivering a preventive vaccine, an effective cure, or both. Yet even a cursory glance at the relationship between scientific/ technical progress and health shows that meeting the scientific challenges is only one step toward effective application of the vaccine or drug. It is typical, not atypical, that hepatitis B vaccine is only now becoming relatively freely available to large populations in the developing world, more than a decade after the vaccine's licensure.