Wilder Penfield (1891–1976) is famous for his contributions to the understanding of epilepsy and for his discoveries of the relationship between the structure and function of the human brain. His operations, which involved stimulating the cerebral cortex of awake patients with a fine electrode, assured the complete removal of lesions that caused epilepsy. Less widely known is his use of the same technique to localize the interpretation of language, the recording of memories, and the ability to interpret the present in light of past experience. Radical Treatment follows the evolution of Penfield’s thinking from his description of brain scars at the beginning of his career to his last thoughts on the human condition. Through a review of his clinical charts, intraoperative sketches, manuscript notes, and other archival material held at the Montreal Neurological Institute and Hospital, this book presents a fascinating narrative of the development of Penfield’s career and the processes that led to each of his great discoveries. Richard Leblanc vividly conveys the collaborative nature of Penfield’s work at the Royal Victoria Hospital and at the MNI, which led to his greatest discoveries. Revealing the duality of a life in science, Leblanc shows that while Penfield was instrumental in establishing the localization of specific functions to distinct regions of the brain, he concurrently stressed the integrative action of the nervous system. Written by the leading authority on the history of Penfield’s Montreal Neurological Institute, Radical Treatment is an insightful account of the scientific accomplishments of one of the twentieth century’s most influential neuroscientists.