Psychiatrists have generally reacted nonchalantly to the relatively sudden eruption of bulimia nervosa some 50 years ago. Admittedly, its clinical description in 1979 secured its place in the main systems of classification, a place which has stood the test of time. Effective treatments have also been developed. But little is known about the aetiology of bulimia nervosa even though there must have been powerful reasons for its appearance out of the blue. The clarification of its causes would certainly have been faster had psychiatrists and social scientists wakened sooner to the significance of bulimia nervosa as a new psychiatric disorder.