This book broadly discusses Autism Spectrum Disorders (ASD) and its related aspects. Many researches are being conducted in the field of ASD and substantial efforts are being made to study it. It is usually difficult for any professional to keep pace with the current developments in this field. This book includes contributions of expert clinicians and renowned researchers from all over the world. It aims towards providing latest information and advances in the area of ASD. It gives broad overview of the topics which may be unfamiliar to researchers and clinicians. The topics have been organized under three sections: prevalence & diagnosis, etiological factors - general overview and genetics.