This volume contains the main proceedings of the fourth international conference on "Cancer Prevention 2006," which was held during February 16–18, 2006, in St. Gallen, Switzerland. Written by international experts in the field, the book comprises a comprehensive update on the most recent developments in the upsurging fields of molecular biology and cancer genetics and their interactions with clinical epidemiology and cancer prevention at various levels: genetic/biologic predisposition and definition of high-risk groups; preclinical models and tumor prevention; prospects of surrogate endpoints and biomarkers; progress in imaging and detection of neoplastic precursor lesions; problems with Cox-2 inhibitors in tumor chemoprevention; primary and secondary prevention of gynecological, breast, gastrointestinal and genitourinary cancers. In addition, the future prospects of cancer chemoprevention are discussed.