Based on the presentations given by well-known specialists at a recent multidisciplinary conference of developmental psychobiologists, obstetricians, and physiologists, this book is the first exhaustive attempt to synthesize the present scientific knowledge on fetal behavior. Utilizing a psychobiological analytic approach, it provides the reader with an overview of the perspectives, hypotheses, and experimental results from a group of basic scientists and clinicians who conduct research to elucidate the role of fetal behavior in development. Experimental and clinical as well as human and animal data are explored via comparative developmental analysis. The ontogeny of fetal spontaneous activity -- via the maturation of "behavioral states" -- and of fetal responsiveness to sensory stimulation is studied in detail. Results are provided from studies of embryonic/fetal and newborn behavior in chicks, rats, sheep, primates, and humans. Knowledge of fetal behavior is crucial to the obstetrician, neonatologist, developmental psychologist, and even the future parents, in order to follow and assess the gradual development of spontaneous responsive movements of the fetus. While assessing this important information, this text also examines the neuro-behavioral events taking place during the fetal period as an aid to understanding normal and pathological life span development.