Toch sets out to question the theory enunciated by Aichhorn: that delinquency is characterized by ego defect. He reviews the work of Freud, Hartmann, and Alexander and states that nothing written about ego psychology enables one to draw the conclusion that the delinquent's ego is defective. On the contrary, he sees the delinquent as having developed an ego which is adapted to a particular environment, termed the 'low probability environment', characterized by crisis, instability, and social disorganization. Therapeutic assumptions based on development of an ego in a high probability environment are not useful in dealing with delinquency, which is a problem secondary to environmental disruption. Efforts at change must involve reorientation of the person as one converts his environment into a more satisfying and rewarding form.