This volume contains the majority of the invited keynote lectures presented by experts at the Third International Conference on Controversies in Tumor Prevention and Genetics on 12-14 February 2004 in St.Gallen, Switzerland. Together, they reveal the latest findings in oncogenetics and its relations to recent and future developments in primary and secondary tumor prevention, especially in breast, colon and lung cancer. All contributions are written and have been critically reviewed by internationally recognised leaders in the field.