Autism is a disorder that uniquely impacts core aspects of socialization. Since its first description by Kanner in 1943 a considerable body of knowledge has developed. It has traditionally been defined by a triad of impairments – in social interaction (autism), communication, and restricted interests & repetitive behaviors. Autism is an early onset disorder with a strong genetic basis and clear evidence of brain involvement. Progress has occurred in the areas of earlier diagnosis, provision of more effective management and in understanding the nature of the social brain difficulties in both autism and related conditions.