This book offers a state of knowledge on the main theories that explain the psychological development of the child and the adolescent. Starting with a presentation of the history of developmental psychology, the chapters are organized around the various authors who have developed models of the different stages of development. The book also provides valuable insights into the psychological development of the child in sub-Saharan Africa.The book is primarily intended for students of psychology. It is also intended for professionals engaged in educational careers. It has a clear and didactic structure with the deliberate intention of making it accessible to all.