This monograph is based on 20 years of research with patients who have experienced pathology in one hemisphere of the brain. It deals with brain mechanisms in human communicative behavior, and with related motor functions, from a broadly biological point of view. In so doing, the work discusses the possible evolutionary origins of human communication, the relation of brain mechanisms in communicative behavior to analogous nonhuman behaviors, and the neural systems involved in various levels and kinds of communication. In addition, noncommunicative mechanisms which parallel those used in...