An important component of Division TEACCH''s mandate from the Department of Psychiatry of the University of North Carolina School of Medicine and the North Carolina State Legislature is to conduct research aimed toward improving the understanding of developmental disabilities such as autism and to train the professionals who will be needed to work with this challenging population. An important mechanism to help meet these goals is our annual conference on topics of special importance for the understanding and treatment of autism and related disorders. As with the preceding books in this series entitled Current Issues in Autism, this most recent volume is based on one of these conferences. The books are not, however, simply published proceedings of conference papers. Instead, cer tain conference participants were asked to develop chapters around their pres entations, and other national and intemational experts whose work is beyond the scope of the conference but related to the conference theme were asked to contribute manuscripts as weil. These volumes are intended to provide the most current knowledge and professional practice available to us at this time.