The third edition of Cancer Epidemiology and Prevention represents a comprehensive update of information that has increased dramatically since the publication of the second edition in 1996. Once again the volume addresses the global burden of cancer, the complex interrelationship of environmental and genetic factors involved in the induction and progression of a broad spectrum of malignancies, and the current priorities and challenges in cancer epidemiology and prevention research. Cancer incidence and mortality is universal, but the burden of cancer classified by morphology and organ site is distributed unevenly in different populations around the world. In developing countries the populations are disproportionately affected by cancers related to infectious agents, while in industrialized countries a large percentage of cancers are associated with lifestyle factors including smoking, obesity, and physical inactivity. The heavy worldwide toll of cancer can be gauged in a survey of the International Agency for Research on Cancer, which estimated that in 2002 there were 10.9 million cancers diagnosed, 6.7 million cancer deaths, and 24.6 million persons living with cancers detected within the previous 5 years. In the United States, cancer mortality in men and women younger than 85 years has surpassed heart disease as the leading cause of death since 1999, although cancer mortality is still less common than heart disease after age 85.