The suggestion that cancer incidence rates for different parts of the world should be brought together in ~ single volume arose in diSCUssion among mem bers of the Geographical Pathology Committee of the International Union Against Cancer during a symposium in Mexico in .1964. That there was a need for such a volume rapidly became apparent when the directors of cancer registries were asked for their opinion. Of those approached, all but one responded enthusias tically and immediately agreed to contribute. In the event, data have been col lected from 32 cancer registries in 24 countries, and 39 scientists have con tributed personally by describing the character of their registry and by collec ting and submitting figures in a standard way. The form in whiCh the book appears was suggested by a committee of 15 members, which met at the Ciba Foundation in London in May, 1965, and the editors have been guided in their work by the results of the discussions that took place at that meeting. In a few instances, it has not been possible to follow the Committee's advice, for reasons of finance, and the text which was written by the editors may, in some places, have inadvertently misrepresented the Committee's views. The editors, therefore, take full personal responsibility for all defects in both style and scientific presentation.

The effects of circadian rhythms on human performance in general and on response to exercise in particular are a well-known phenomenon. Often after a poor night's sleep or taking a "red-eye" flight into a different time-zone, one just doesn't feel like "themselves." This book aims to provide a comprehensive account of biological rhythms and how they affect exercise. Particular attention is given to sleep, its biological function, and the consequences for exercise performance of sleep loss. There are chapters devoted to the effects of disturbing the circadian body clock, such as when multiple time zones are crossed and jet-lag experienced. The effects of nocturnal shift work and seasonal variation are also covered. The interactions between exercise and the female menstrual cycle are explained and the issue of exercise during pregnancy discussed. Finally, there is a chapter devoted to research methods in chronobiology, the scientific discipline underpinning the content of the book.