Alfred Adler developed Individual Psychology, which viewed human motivation as striving for perfection and superiority. He believed people develop styles of life early in childhood based on feelings of inferiority and their way of compensating. Adler emphasized social interest and saw neurosis as a lack of concern for others. Key concepts included masculine protest, birth order influences, and understanding people holistically rather than by internal traits. Adler assessed personalities through early memories, dreams, and expression styles.