Describes what developmental theories are, where they come from, how they work, and how they can be used to explain human nature. This book is written primarily for psychology and education students whose programs include a course in child psychology, child development, or theories of development. The text may also be used to supplement courses on child development organized thematically or chronologically. Instructors of graduate courses in child development may wish to consider this text as a primary synthesis containing more source material and source citations than others of its kind. The primary aim of the book is to describe what developmental theories are, what they can do, where they come from, how they work, and how they can be used to explain human nature.