The Illinois Test of Psycholinguistic Abilities (ITPA) is treated in terms of the ability measured, hints for administration and scoring, and questions often asked for each of the nine subtests. Typical profiles are described and analyzed for mentally retarded, kindergarteners, slow learners, culturally disadvantaged, Negroes, good and poor readers, articulation defective, aphasic and aurally handicapped, visually handicapped, cerebral palsied, and gifted. The ITPA and reading are discussed with profiles and tentative generalizations made. Patterns of deficiencies in profiles corresponding to the three dimensions of language postulated in the model of the ITPA and individual ITPA profiles are interpreted for visual problems, the Strauss Syndrome, shyness, encoding disability, and an effeminate mentally retarded male. Auditory vocal channel disabilities are discussed in detail with graphs. The reliability of clinical judgment is treated and considerations for comparing and contrasting profiles with different subtest scores are given. A 122-item bibliography and a total of 43 profiles are included. (SN)