This is the second and final resubmission to seek renewal of funding for the R25 education program, Nutritional Epidemiology of Cancer. The previous review summary concluded that "This is a very strong and unique program. Dr. Stampfer appears to have addressed most of the problems raised in the earlier application. This is an outstanding program." The original proposal was submitted with the encouragement and advice of the NCI Training Branch. Advancing nutrition research through expanded education and training programs is a high priority of the Division of Cancer Prevention at the National Cancer Institute. This program includes provision of sustained leadership, dedicated faculty time, a well-defined specialized curriculum, interdisciplinary research environments, and two (or more) mentors for each trainee. This interdisciplinary, yet focused, program is based on the interface of nutrition and epidemiology. It is led by Dr. Meir Stampfer, with Dr. Walter Willett as co-Principal Investigator, Dr. Edward Giovannucci as Education Director and Dr. Stephanie Smith-Warner as Associate Education Director, and addition of Dr. Lorelei Mucci. The ultimate goal is to train researchers to discover new ways in which changes in diet can reduce the risk and burden of cancer. The program, now in its sixth year (through a no-cost extension), already has established a solid record of achievement. It has drawn on the wealth of other resources from the Departments of Epidemiology and Nutrition at the Harvard School of Public Health, which has long been a recognized center for didactic and practical training in epidemiologic methods, cancer epidemiology in general, and nutritional epidemiology. This educational program also draws on diverse research opportunities within the Dana-Farber/Harvard Cancer Center (DH/HCC), a matrix cancer center representing cancer research across seven Harvard-affiliated institutions. The R25 draws upon major developments in the area of diet and cancer such as the creation of three large cohorts comprising over 250,000 men and women followed for as long as 28 years with repeated measures of diet. Through this training grant, we have brought together the various elements already in place, and created new elements to build a coherent and focused interdisciplinary program in the nutritional epidemiology of cancer. The Nutritional Epidemiology of Cancer program provides a unique niche, while being complementary and synergistic with the other training grants in order to foster a strong environment, based on sound biology, for cancer prevention and control. This new program has already demonstrated remarkable success in attracting outstanding candidates. Trainees who have completed the program have uniformly embarked on promising careers in this area.