As widespread social transformations have been paralleled by gains in health and life expectancy through public health and other improvements, a variety of new obstacles to health have emerged. Lifestyle-related, behaviorally mediated changes in rates of chronic disease are the most prevalent of these new challenges. This book examines the relationship between human biology and human society, and how behavior, hormones, and health intersect. There is both scientific interest and practical urgency behind the ideas and findings presented here, as the need for a socioecological view of function and well-being has become more apparent. This book documents an emerging understanding of how hormones create the linkage between behavior or social life and health.