This handbook guides the mental health therapist working with children and adolescents through their natural language of play. Opening with an extensive review of the neurodiversity paradigm and ableism, the chapters cover AutPlay® Therapy protocol, phases of therapy, assessment strategies, and common need areas along with understanding neurodiversity affirming processes. Additional chapters highlight the therapeutic powers of play, integrative play therapy approaches, understanding co-occurring conditions, working with high support needs, and using AutPlay® Therapy to address regulation, sensory, social/emotional, and other mental health concerns that neurodivergent children may be experiencing. The handbook serves as a thorough guide for play therapists, child therapists, and family therapists who work with neurodivergent children and their families.