1. Theories of Communication Development.- 2. Research on Nonlinguistic Communication Functioning of Individuals with Severe or Profound Handicaps.- 3. Intervention Models to Develop Nonlinguistic Communication.- 4. The Sonoma Research Project: Facilities, Population Communication Needs, and Subjects.- 5. The Sonoma Research Project: Issues, Variables, and Methods of Investigation.- 6. The Sonoma Research Project: Data Analysis Design and Results.- 7. The Sonoma Research Project: Discussion and Conclusions.