This book discusses the complex relationships between diet and major diseases of western civilization, such as cancer and atherosclerosis. It begins with an overview of research strategies in nutritional epidemiology, a relatively new discipline that combines the body of detailed knowledge gained by nutritionists in this century with methodologic approaches developed by epidemiologists to study determinants of diseases with multiple etiologies and long latent periods. Learning about the effects of diet begins with its measurement, thus a major part of the book is devoted to methods of dietary assessment using data on food intake, biochemical indicators of diet, and measures of body size and composition. The reproducibility and validity of evidence from each approach and the implications of measurement error are considered in detail. The analysis, presentation, and interpretation of data from epidemiologic studies of diet and disease are discussed; particular attention is given to the influence of total energy intake on the findings of these studies. Comprehensive and in-depth, this is an indispensable text for epidemiologists, nutritionists, and their students.