The etiology of the Autistic Spectrum Disorders is discussed with a focus on Asperger's disorder. The manifestation of the triad of social impairment, communication impairment, and restricted repetitive behaviors and interests is discussed in terms of the various symptom phenotypes comprising these three domains. Clinical case material is used to illustrate how the treatment modality utilized should be fitted to an individual child's needs. A multimodal treatment plan is considered optimal in order to achieve a successful therapeutic outcome.