Before Gertrude Stein became the twentieth century s preeminent experimental writer, she spent a decade conducting research in both the leading psychological laboratory and the leading medical school in the United States. This book unearths the turn-of-the-century scientific and philosophical worlds in which the young Stein was immersed, demonstrating how her extensive scientific training continued to exert a profound influence on the development of her extraordinary literary practices. As an undergraduate, Stein worked with the philosopher William James and the psychologist Hugo M nsterberg at the Harvard Psychological Laboratory, investigating secondary personalities and automatic writing. Later, at Johns Hopkins Medical School, she was involved in cutting-edge neuroanatomical research in the laboratory of Franklin Mall, the leading anatomist and embryologist of the day, and his assistant Lewellys Barker, the author of the first English-language textbook to describe the nervous system from the standpoint of the newly established neuron doctrine. Just as scientists reconceived relations among neurons as a function of contact or contiguity, rather than of organic connection, Stein radically reconceptualized language to place equal weight on the conjunctive and disjunctive relations among words.