Bryna Siegel, PhD, is Director of the Autism Clinic and Co-Director of the Autism and Neurodevelopment Research Center at the University of California, San Francisco. She has worked with children with autism and their families for 25 years, and has developed diagnostic tools and guidelines used by professionals nationwide. Dr. Siegel is an active lecturer and consultant whose previous books include the bestselling The World of the Autistic Child.

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