Timothy R. Vollmer received his Ph.D. from the University of Florida in 1992. From 1992 until 1996, he was on the psychology faculty at Louisiana State University. From 1996 to 1998, he was on the faculty at the University of Pennsylvania Medical School. He returned to the University of Florida in 1998 and is now a professor of psychology. His primary area of research is applied behavior analysis, with emphases in developmental disabilities, reinforcement schedules, and parenting. He has published more than 130 articles and book chapters related to behavior analysis. He was the recipient of the 1996 B.F. Skinner New Researcher award from the American Psychological Association (APA). He received another APA award in August 2004, for significant contributions to applied behavior analysis. He is a former ABAI council member. He is currently the editor-in-chief of the Journal of Applied Behavior Analysis, a board member on the Society for the Experimental Analysis of Behavior, and an ABAI fellow. Abstract: Autism spectrum disorders (ASD) are defined, in part, by restricted inflexible behavior. At the Behavior Analysis Research Clinic at the University of Florida, Dr. Vollmer has been collaborating with colleagues and students to evaluate such behavior in a range of contexts. One, they have compared the behavior in children with ASD to typically developing children using arbitrary play activities. Although both groups showed restricted interests, the ASD children were far less likely to switch activity upon request to do so. Two, they have extended their work on restricted inflexible behavior to socially relevant activity such as restricted food interests and restricted interest in sedentary activity such as video games, videos, and computer surfing. They are examining shaping procedures to increase variability in responding. Three, they have evaluated repetitive behavior disorders such as stereotypy and severe self-injury. They are currently investigating emergency treatment procedures for situations when a single instance of problem behavior may be too dangerous. Results from this collection of studies will be presented and discussed.