Aside from such personal prerequisites as superior intellect, high degree of motivation, integrity, and ability to tolerate ambiguity, Curtis delineates four categories of prerequisite: (1) clinical experience, with an underlying emphasis on training in psychotherapy; (2) a background in the humanities; (3) some knowledge of science and the scientific method; and (4) "socialization into a profession with group norms." After discussing the criteria for selection of psychoanalysts from the medical-psychiatric background, Curtis considers the integration of other fields into the system. Although he does not rule out other professionals, such as lawyers and social workers, he cites two groups that more clearly fit into the above criteria: persons with doctorates in clinical psychology or those in mental health programs. While these two groups differ from each other, in both of them the author's four necessary criteria are met.