Book excerpt: During the past twenty years there has been a dramatic increase in obesity in the United States. An estimated thirty percent of adults in the US are obese; in 1980, only fifteen percent were. The issue is gaining greater attention with the CDC and with the public health world in general. This book will offer practical information about the methodology of epidemiologic studies of obesity, suitable for graduate students and researchers in epidemiology, and public health practitioners with an interest in the issue. The book will be structured in four main sections, with the majority of chapters authored by Dr. Hu, and some authored by specialists in specific areas. The first section will consider issues surrounding the definition of obesity, measurement techniques, and the designs of epidemiologic studies. The second section will address the consequences of obesity, looking at epidemiologic studies that focus on cardio-vascular disease, diabetes, and cancer The third section will look at determinants obesity, reviewing a wide range of risk factors for obesity including diet, physical activity and sedentary behaviors, sleep disorders, psychosocial factors, physical environment, biochemical and genetic predictors, and intrauterine exposures. In the final section, the author will discuss the analytical issues and challenges for epidemiologic studies of obesity.