One of Freud's central achievements was to demonstrate how unacceptable thoughts and feelings are repressed into the unconscious, from where they continue to exert a decisive influence over our lives. This volume contains a key statement about evidence for the unconscious, and how it works, and major essays on the fundamentals of mental functioning. Freud explores how we are torn between the pleasure principle and the reality principle, how we often find ways both to express and to deny what we most fear, and why people so often need fetishes for their sexual satisfaction. These studies brilliantly illuminate our most basic drives and how they are transformed.