Theories of personality are frameworks that aim to explain the patterns of thoughts, feelings, and behaviors that make individuals unique. Major theories include Sigmund Freud's psychoanalytic theory, which emphasizes the influence of the unconscious mind, and Carl Rogers' humanistic theory, which focuses on personal growth and self-actualization. Other notable theories include B.F. Skinner's behaviorist approach, which highlights the role of environmental factors in shaping personality, and Hans Eysenck's trait theory, which categorizes personality into dimensions like extraversion and neuroticism. Each theory offers different insights into how personality develops and functions.