This critical history of research on acquired language deficits (aphasias) demonstrates the usefulness of linguistic analysis of aphasic syndrome for neuropsychology, linguistics, and psycholinguistics. Drawing on new empirical studies, Grodzinsky concludes that the use of grammatical tools for the description of the aphasias is critical. The selective nature of these deficits offers a novel view into the inner workings of our language faculty and the mechanisms that support it.

In contrast to other proposals that the left anterior cerebral cortex is crucial for all syntactic capacity, Grodzinsky's discoveries support his theory that this region is necessary for only a small component of the human language faculty. On this basis he provides a detailed explanation for many aphasic phenomena - including a number of puzzling cross-linguistic aphasia differences - and uses aphasic data to evaluate competing linguistic theories.