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.