1. The Minnesota Multiphasic Personality Inventory (M. Inventory) was evaluated by application to 416 United States Army enlisted personnel. Results in this study present convincing evidence that the test is a valuable psychometric adjunct to clinical psychiatric practice.2. It does not establish definitive diagnoses; it sometimes overemphasizes certain personality distortions and minimizes others; it requires interpretation in the light of the total clinical picture; it is not a substitute for the psychiatrist.3. Anxiety may be satisfactorily measured by averaging the scores of the first three M. Inventory scales, hypochondriasis (Hs), depression (D), and hysteria (Hy), to form an A (anxiety) score.4. The M. Inventory elicits significant data in several psychosomatic illnesses. In migraine, post-traumatic headache, epilepsy, somnambulism and enuresis it meets clinical expectations to a high degree.5. M. Inventory retests at intervals prove dependable in following the clinical course and helpful in determining the prognosis.6. The M. Inventory makes its most constructive contribution to clinical medicine in illuminating the study of individual cases through combinations of its multiple scores which reveal many facets of the disturbed personality.Technical assistance was rendered by Sgt. Robert Stewart, Sgt. Alvin Brookman, and Cpl. Sidney Noble.