The large number of recent reviews testify to the importance of modelling in the experimental and clinical literature on behaviour modification (Bandura, 1969, 1971; Flanders, 1968; Goldstein, 1973; Rachman, 1972, 1975).The initial resurgence of interest has been, without doubt, largely due to Bandura's experimental investigations of imitation learning, and his assignment of modelling to a central role in his social learning theory (Bandura, 1971). He and his colleagues have demonstrated the importance of modelling in such diverse areas as aggression, anxiety-reduction, self-control and the acquisition of moral judgements. In very recent years there has been a veritable explosion of studies with direct or indirect relevance to a clinical population. This is exemplified in the two reviews conducted by Rachman. Prior to 1972, seventeen experimental investigations had appeared. In the next two years a further twenty-six studies were reported (Rachman, 1972, 1975).