This article creates a strong theoretical rationale in support of the concept of fellowship, the cornerstone healing influence of Alcoholic Anonymous (AA). It reviews the literature which supports the Alcoholic Anonymous' concept of fellowship or client perceived belongingness. It provides a strong rationale for the establishment of new AA-oriented programs which can be used to convince regulatory agencies of the worth of these programs. It provides information supporting the AA premise that feelings of belongingness are a significant factor in consideration of good mental health and psychological treatment outcome. This provides a common ground of agreement between the AA community and the psychological/psychiatric community. This article is divided into four subsections: (1) literature related to personality theory; (2) literature related to group psychotherapy; (3) literature related to alcoholism pathology; and (4) literature related to alcoholism psychological treatment. References are included. (ABL)