Guntrip points out that psychoanalytic theory has always been in a state of continuous development, but during Freud's lifetime virtually all the fundamentally new ideas came from Freud himself. Guntrip then offers a highly condensed critical review of the main aspects of psychoanalytic theory; of some of the modifications promulgated by Horney, Fromm, Sullivan, Klein, and Fairbairn; and, finally, an evaluation of some of these modifications. The author feels that the advocates of the 'culture pattern' theory have provided material of 'more descriptive importance … than explanatory value in idealogical depth'. Guntrip is more impressed with the work of Klein and Fairbairn, whose achievement has been 'in carrying the concept of object relationships into the investigation of the total psyche'. He believes that the most urgent task now confronting psychoanalysis is reinvestigation of the whole problem of psychotherapy in terms of the theory of object-relations, particularly with a view to understanding the part played by the relationship of analyst and patient as the real therapeutic factor.