Until very recently, almost all books on infancy assumed basic infant immaturity. Remarkably, as Tiffany Field shows in her survey of recent research, investigators are discovering that infants possess sophisticated perceptual skills, such as hearing, even before birth. Newborns can sense touch and motion, discriminate tastes and smells, recognize their mother's voice, and imitate facial expressions. In fact, the newborn is an active learner, looking,...