To survive as a species man must adapt. But genetically he is largely the same as his Stone Age ancestors. It is not surprising that drastic modifications of the environment which have taken place have given rise to many signs of man's maladjustment. The impact of civilisation on the biology of man, evidenced by the effects of diet, crowding, noise, the changing nature of disease, and the stress of modern living, was the subject of critical examination by distinguished scientists at a symposium sponsored by the Australian Academy of Science in 1968.