This fourth edition of the best-selling topically-organized introduction to infancy reflects the enormous changes that have occurred in our understanding of infants and their place in human development over the past decade. Each chapter has been thoroughly revised to reflect current thinking and research in the field, and while classic studies continue to be cited, the text emphasizes studies published since the late 1990s. The authors have worked to maintain the readability for which this classic textbook has been known. This edition continues to be appropriate for use in classes at all levels--undergraduate and graduate--as well as in various disciplines--psychology, education, child development, nursing, and social work. The fourth edition features a number of improvements: *the literature review has been thoroughly updated to reflect the results of new research; *new figures have been provided to better explain important concepts and the results of recent studies; *implications for practical applications and social policy have been emphasized throughout; *the writing style has been revised to make the book attractive to students from diverse academic backgrounds; and *orienting questions have been provided at the beginning of each chapter to facilitate understanding and learning.