In the course of theorizing about psychoanalysis, Freud changed his mind on some important matters. Perhaps the most striking was his revision of instinct, or drive, theory. Beyond the Pleasure Principle, published in 1920, is the first clear statement of Freud's new drive theory: love and life now stand over against agression and death. The book represents an important theoretical revision of Freud's earlier ideas and a turning point in psychoanalytic theory.
from the publisher's website