The authors argue that fifty years after the initial publication of W. R. D. Fairbairn's object-relations theory of the personality, his ideas have moved to the centre of psychoanalysis and provide the most cogent theoretical rationale for many modern concepts of technique and the therapeutic action of psychoanalysis. In particular, Fairbairn centred object-relations theory on the person's need for relationships from infancy and throughout life, and gave the first detailed description of the sequential processes of internalisation of the rejecting object, followed by splitting of the ego and repression of painful internal object relations. He described the way these processes led to the organisation of the ego as an internal system of subegos and part objects (which are actually organisations of the ego, too) which are always in dynamic interaction with each other and which determine the quality of external relationships. This paper draws on Fairbairn's early writings, many of them recently published for the first time, to describe the origin of Fairbairn's ideas in his study of philosophy, to outline his theory of object relations, and to consider current developments and applications of these ideas in psychoanalysis and beyond.