Beginning in the 1990s, behavioral scientists—that is, people who study mind, brain, and behavior—began to take the theory of evolution seriously. They began to borrow techniques developed by the evolutionary biologists and apply them to problems in mind, brain, and behavior. Now, of course, virtually all behavioral scientists up to that time had claimed to endorse evolutionary theory, but few used it to study the problems they were interested in. All that changed in the 1990s. Since that pivotal decade, breakthroughs in the behavioral and brain sciences have been constant, rapid, and unremitting. The purpose of the Brain, Behavior, and Evolution series of titles published by ABC-CLIO is to bring these new breakthroughs in the behavioral sciences to the attention of the general public. In the past decade, some of these scientifi c breakthroughs have come to inform the clinical and biomedical disciplines. That means that people suffering from all kinds of diseases and disorders, particularly brain and behavioral disorders, will benefi t from these new therapies. That is exciting news indeed, and the general public needs to learn about these breakthrough fi ndings and treatments. A whole new fi eld called evolutionary medicine has begun to transform the way medicine is practiced and has led to new treatments and new approaches to diseases, like the dementias, sleep disorders, psychiatric diseases, and developmental disorders that seemed intractable to previous efforts. The series of books in the Brain, Behavior, and Evolution series seeks both to contribute to this new evolutionary approach to brain and behavior and to bring the insights emerging from the new evolutionary approaches to psychology, medicine, and anthropology to the general public.