In the mid-nineteenth century, physicians observed numerous cases in which individuals lost the ability to form spoken words, even as they remained sane and healthy in most other ways. By studying this condition, which came to be known as "aphasia," neurologists were able to show that functions of mind were rooted in localized areas of the brain. Here L. S. Jacyna analyzes medical writings on aphasia to illuminate modern scientific discourse on the relations between language and the brain, from the very beginnings of this discussion through World War I. Viewing these texts as literature--complete with guiding metaphors and rhetorical strategies--Jacyna reveals the power they exerted on the ways in which the human subject was constructed in medicine. Jacyna submits the medical texts to various critical readings and provides a review of the pictorial representation involved with the creation of aphasiology. He considers the scientific, experimental, and clinical aspects of this new field, together with the cultural, professional, and political dimensions of what would become the authoritative discourse about language and the brain. At the core of the study is an inquiry into the processes whereby men and women suffering from language loss were transformed into the "aphasic," an entity amenable to scientific scrutiny and capable of yielding insights about the fundamental workings of the brain. But what became of the subject's human identity? Lost Words explores the links among language, humanity, and mental presence that make the aphasiological project one of continuing fascination.