This book provides data on the effectiveness of Applied Behavior Analysis (ABA), one of the effective methods for educational and therapeutic approaches with children on the autism spectrum. The research was conducted over ten years with a total of 30 children, who demonstrated significant developmental potential by, for example, learning verbal language, making eye contact, understanding instructions from others, imitating, initiating interactions, and playing. Based on this research, important conclusions have been drawn for the therapy of children on the autism spectrum. A special section of the book features the individual stories of the children, written by their parents.