Nathan H. Azrin, Ph.D., is the father of four children and a leading authority on the psychology of learning. He currently heads the Behavior Research Laboratory at Anna State Hospital, Anna, Illinois, and is Professor of Rehabilitation at Southern Illinois University. A cum laude graduate of Boston University, Dr. Azrin received his Ph.D. in psychology in 1956 at Harvard University, where he helped develop programmed arithmetic instruction for primary-school children. He was a research associate at the Boston University School of Medicine and also participated in experimental studies of learning disabilities in children. Before taking his present post in Illinois in 1957, he was a research psychologist at the Institute of Living in Hartford, Connecticut, and performed studies of learning and motivation factors while serving in the United States Army. Dr. Azrin has been a lecturer in the Psychology Department of Harvard University. He is a member and fellow of the American Psychological Association, and a past president of both the Society of the Experimental Analysis of Behavior and Division 25 of the American Psychological Association. He has been an editor of the Journal of Applied Behavior Analysis and the Journal of the Experimental Analysis of Behavior. Dr. Azrin has published over 100 studies in the field of learning and psychological treatment. He is co-author (with Teodoro Ayllon) of The Token Economy: A Motivational System for Therapy and Rehabilitation and (with Richard M. Foxx) of Toilet Training the Retarded. Richard M. Foxx, Ph.D., is a research psychologist for the state of Illinois Department of Mental Health, affiliated with the Behavior Research Laboratory, Anna State Hospital, Anna, Illinois, where he develops intensive learning programs for the institutionalized mentally ill and retarded and training programs for out-patient children both normal and retarded. A graduate of the University of California (Riverside) and California State University (Fullerton), Dr. Foxx received his Ph.D. in educational psychology from Southern Illinois University in 1971 with a dissertation on the use of overcorrection procedures in a classroom for retarded children. As a Research Assistant at Patton State Hospital, Patton, California, and at Pacific State Hospital, Pomona, California, he worked in remotivation programs for the adult mentally ill and for retarded adolescent females. Dr. Foxx currently teaches a course in child psychology at Southern Illinois University. He is a member of the American Psychological Association and of the Child Psychology, Experimental Analysis of Behavior, Clinical Psychology and Mental Retardation divisions within that association. He is also a member of the National Society for Autistic Children, the Association for the Advancement of Behavior Therapy and the American Association on Mental Deficiency. Dr. Foxx has published widely on the learning process and developed many educational programs for both normal and disordered individuals. He is co-author (with Nathan H. Azrin) of Toilet Training the Retarded.Azrin, Nathan H. is the author of 'Toilet Training in Less Than a Day', published 1989 under ISBN 9780671693800 and ISBN 0671693808.