This document provides an overview of 17 prominent theories and theorists in psychology and their key contributions. It summarizes the main tenets of each theory, including Psycholinguistic Theory by Noam Chomsky, Maslow's Hierarchy of Needs by Abraham Maslow, Constructivist Learning Theory by Lev Vygotsky, Social Cognitive Theory by Albert Bandura, Psychoanalysis Theory by Sigmund Freud, Psychosocial Development by Erik Erikson, Classical Conditioning by Ivan Pavlov, Cognitive Development Theory by Jean Piaget, Individual Psychology by Alfred Adler, theories by Carl Jung, Aaron T. Beck, B.F. Skinner, Albert Ellis, Karen Horney, John Bowlby, and the Milgram obedience experiment