1. Nancy C. Brady, PhD, is an assistant research professor at the Schiefelbusch Institute for Life Span Studies, University of Kansas, where she is an investigator on a program project grant studying communication in persons with mental retardation. She has authored and coauthored many articles on communication development in people with severe disabilities. Address: Nancy C. Brady, University of Kansas Parsons Research Center, 2601 Gabriel, PO Box 738, Parsons, KS 67357.
2. James W. Halle, PhD, is professor of special education at the University of Illinois, Urbana—Champaign. He has written numerous articles and chapters about communication by people with severe disabilities. He is past editor of the Journal of the Association for Persons with Severe Handicaps and is currently the Associate Editor of the Journal of Applied Behavior Analysis.