This document provides an overview of several major theories of child psychology, including psychodynamic, behavioral, and cognitive perspectives. It summarizes Sigmund Freud's psychosexual stages of development from oral to genital. It also outlines Erik Erikson's psychosocial stages from trust vs mistrust to identity vs role confusion. Various behavioral learning theories are mentioned like Maslow's hierarchy of needs, Bandura's social learning theory, and Skinner's operant conditioning. The implications of understanding child psychology for orthodontic treatment are briefly discussed.