On April 18 and 19, 2007, the Institute of Medicine’s (IOM’s) Forum on Neuroscience and Nervous System Disorders, in response to a request from the U.S. Secretary of Health and Human Services, hosted a workshop called “Autism and the Environment: Challenges and Opportunities for Research.” The goal of the workshop was to provide a venue to bring together scientists, members of the autism community, and the major sponsors of autism-related research to discuss the most promising scientific opportunities.