This work examines roots of modern and contemporary language theory in the turn-of-the-century writings of Gertrude Buck, with special emphasis on Composition and literary theory. Three main tasks are set forth: (1) To examine Buck's numerous writings on metaphor, word-thought genesis, argumentation, reader-theory, and social cooperation; (2) To discuss her work in the backdrop of other nineteenth-century rhetoricians and turn-of-the century language theorists and philosophers; (3) To recall Buck's contributions in light of contemporary interest in matters such as collaborative learning, pre-writing and invention, cognitive functions of writing, and reader-response in Composition and literary theory. The conclusion reached is that Gertrude Buck anticipated many of the tenets of today's New Rhetoric, in which meaning is said to result from the transaction of author, reader, language, and reality. Meaning can be viewed as an event of transaction, rather than an unchanging, eternal verity. (Dissertation Abstracts)