Students and professionals alike will find this volume to be a valuable source of information and reference for the field of augmentative and alternative communication (AAC). This handbook outlines the history and growth of the field from its beginnings a few decades ago to its current status as an integral element in the clinical and educational programs of individuals with severe communication disabilities. Principles are presented as a foundation for the development of assessment and intervention procedures and practices within the framework of the communication model and its major components: the means to represent, the means to select, and the means to transmit. Detailed descriptions of symbol sets and systems, access options, and low and high tech communication aids and devices provide a resource for individuals involved in the development and delivery of AAC services. Legislation and funding opportunities which influence the provision of AAC services are presented and discussed along with current legal and ethical issues and future research needs.