The HIV/AIDS epidemic has presented considerable challenges to social researchers to provide detailed and accurate information about sensitive behaviour amongst hidden populations, to develop theories to explain and predict how and why behaviour changes; and to carry out assessments of kwledge, attitudes, practices and the effectiveness of health education interventions in shaping these. This volume draws together examples of invative research which has been conducted in the field of HIV/AIDS and describes the relevance of these methods for research in health behaviour more generally. The chapters are drawn from the work of 12 research groups who, in response to the challenge of HIV/AIDS research, have developed the tools of social research to new degrees of sophistication or put them to use in vel and imaginative ways. While the emphasis in this book is on the methods the researchers have developed, it is in the substantive findings of their studies, and their contribution to our understanding of the epidemic, that the methods have proved their worth. The AIDS epidemic has changed the rule for social research on health and illness. The urgency surrounding the epidemic has given rise to an openness to different disciplines and new approaches within the research community. For example, questions of the reliability and validity of accounts of private behaviour have been given new consideration, as have the theoretical underpinnings of research which looks at vulnerable or disadvantaged groups within society. The developments described in this volume represent the way social science has been taken forward by researchers who have confronted the challenges posed by research on the social dimensions of HIV/AIDS.