Callum & Ethan Knight

 When it comes to challenging the myths about autism and PDA (Pathological Demand Avoidance), brothers Callum and Ethan Knight aren't just speaking out; they're writing their way into hearts and minds.

Callum's best-selling book, The Secrets of My Spectrum, and Ethan's new book, The PDA Effect, have become best sellers in several categories on Amazon.co.uk. And Callum's second memoir, More Secrets of My Spectrum: Autism into Adulthood was released in December 2025.