This bibliographical study summarizes and synthesizes the recent (post-1960) theoretical literature on the differential diagnosis and treatment of the male college under-achiever. The three major classifying schemata which appear independently in the literature, and the seven personality patterns they collectively propose, are described. These patterns are compared, contrasted, and differentiated on the basis of ego syntonia or dystonia. The antiachiever is eliminated due to his identity with the psychopathetic deviate. Discussed are issues and general considerations in the treatment of underachievers, as well as specific considerations for the treatment of each of the four patterns (non-achievement syndrome, psychopathic deviation, hypomania, and Wexler's underachiever) in which positive personality change is likely to result in academic improvement. The thesis is advanced that counseling strategies designed for and applied to selected homogeneous groups of underachievers offer the greatest promise of significant improvement. Modification of the institutional environment is suggested as another mode by which the counselor can assist impulsive (hypomanic and psychopathic) underachievers. (Author)