Carl Gustav Jung was a student of Sigmund Freud, Swiss psychiatrist and founder of the school of analytical psychology. He proposed and developed the concepts of the extroverted and introverted personality, archetypes, and the collective unconscious. The issues that he dealt with arose from his personal experiences. For many years Jung felt as if he had two separate personalities. One introverted and other extroverted. This interplay resulted in his study of integration and wholeness. His work has been influential not only in psychology, but in religion and literature as well.