The author examines the social epidemiology of HIV transmission in its different manifestations in the developing world and in the West, looking at heterosexual and homosexual transmission, sex tourism and prostitution, injecting drug users, haemophiliacs and transfusion recipients. He goes on to look at reports of sociological studies of risk behaviour among men who have sex with men, among heterosexual and bisexual men and women, and among those who share syringes. Drawing on his own research, Michael Bloor presents a critical examination of the different theoretical models of