In the pivotal work, Beyond the Pleasure Principle, Freud builds upon and moves beyond his theory of the single-minded search for pleasure and avoidance of unpleasure. Recognising that his previous theory could not account for all behaviours – for example, a patient who resists cure and holds tight to his or her damaging neurotic fixations – Freud introduces the controversial concept of the 'death instinct.'
The death instinct, in conflict with the life instinct, or Eros, allows Freud to explain apparently perverse neurotic tendencies, such as a patient’s constant return to a traumatic experience, and this repetitive behaviour’s consequent obstruction of analytic treatment. In this seminal work, Freud delineates the meaning behind repetition compulsion and its relationship to the pleasure principle, explained in the light of the organism’s desire to return to an inorganic state. This work is to be immensely inspiring to Klein, who is one of the few followers of Freud to adopt and develop his idea of the death instinct.