Maggie Scarf, a journalist who specializes in the behavioral sciences, here presents a collection of her pieces surveying the controversial frontiers of psychology. In Scarf's lucid, lively portrayal, this rapidly evolving science becomes a parade of intriguing unanswered questions: When does a fetus become a person? To what extent do fetal sex hormones program adult behavior? Why do we need sleep? For every frontier there is a pioneer, and Scarf's method is often to interview or profile a prominent innovator, then consult with at least one of his or her critics for a balanced estimation. In this manner she introduces us to Jane Goodall of chimpanzee fame; Dr. John Bowlby, who has applied animal ethology to the study of human mother-child attachments; the slightly chilling Jose Delgado, who controls animals' behavior by electrical brain stimulation; psychiatric radicals R. D. Laing and Thomas Szasz. Scarf is a clear and responsible journalist who knows how to highlight her writing with a warm personal touch while keeping her own judgments in the background. Her book is an intelligent popular introduction to the range of new thinking on human behavior.