This book is an introduction for non-scientists to the science of behavioral genetics and its broader ethical and social implications. Among the topics covered are how scientists explore the influence of genes and environment on behavior and how such research may challenge our understanding of human nature, personal responsibility, and equality. It is a product of a project on behavioral genetics conducted by the American Association for the Advancement of Science (AAAS) and The Hastings Center. Each chapter begins with a fictional, yet plausible, vignette about an individual seeking answers to a question about behavior. The text then provides enough scientific background for the reader to address the question thoughtfully. A glossary indexed according to the chapters explains key words and concepts.