The Ego and the Id (1923)

In this major work Freud lays out his second structural theory of the mind, comprised of the Id, the Ego, and the Superego. In doing so he did not so much supplant his first map of the mind, as build upon and revise it. Freud goes on to describe the Oedipus conflict in more detail than he has done hitherto, revealing the bisexuality inherent in all psyches. The work also reasserts the importance of the death instinct, underlining the centrality of the struggle between the life and death drives in pathological individuals, especially depressive patients.