Interest in autism spectrum disorders (ASDs) has seen an amazing growth among researchers, the government, and the popular press, particularly during the past decade. It is undoubtedly the most studied and talked about topic in developmental disabilities, if not the entire field of mental health. Many states have now included services for ASD in their state health insurance benefits. In addition, popular trade books on ASD have appeared with increasing regularity on The New York Times bestseller list. The increase in popular interest has also provided support for a dramatic uptick in research funding and publications as well as expanded clinical services. For these and other reasons, publishing in the field of ASD has proliferated at a rapid pace, with more than 19,000 articles published on the topic in roughly the past decade. This handbook – with its increased coverage of psychosocial methods – complements already-published works and also fills an information gap in the market. Areas of coverage include perception and cognition, nosology, neuropsychology, social skills, diagnosis, developmental course, comorbid psychopathology, scale development, challenging behaviors, and theory of mind. This volume is important and timely – a must-have resource for researchers, professors, and allied professionals.