Autism spectrum disorder (ASD) is a wide term that is used to define a group of neurodevelopmental disorders. The primary signs of autism spectrum disorders are problems with social interaction and communication. Affected people show repetitive, restricted and stereotyped patterns of behavior. There are different subtypes of autistic spectrum disorders such as with or without accompanying language impairment, with or without accompanying intellectual impairment and associated with another neurodevelopmental or behavioral disorder. Some people can be diagnosed with more than one subtype of autistic spectrum disorders. Early symptoms of ASD are delay in language and social development. There is no single cause of ASD. This book aims to shed light on some of the unexplored aspects of autism spectrum disorders and the recent researches in this field. Its objective is to give a general view of the disorders that come under autism spectrum disorder. Those with an interest in this field would find this book helpful.