Client writing has been used in association with individual therapy for many years, but published research on its effectiveness is sparse. Such research could provide a potential tool for therapists, as well as expand scientific knowledge. This review includes all available reports on the topic of client writing in individual therapy. The studies fall into three general categories: the systematic, "experimental" studies; the anecdotal reports; and the didactic reports. All studies considered show some benefit from the use of client writing in therapy. Writing appears to be beneficial whether initiated by the client or directed by the therapist; beneficial to adolescents and adults of all ages; beneficial to hospitalized patients, clients in individual therapy, and to students in school counseling; beneficial with different forms of writing; beneficial with different types of therapy; and beneficial whether writing is the main focus of therapy or only an adjunctive process. However, the conclusion that client writing is beneficial is largely based on anecdotal reports from therapists who have accidentally stumbled on it. Much more systematic research is needed, beginning with a survey to determine how extensive is its use. Specific recommendations for research are made.