He's been the face of, and driving force behind, kids' television in New Zealand for decades. But Jason Gunn is turning over a new leaf - literally - with the release of a book he's co-written with his brother Andrew. It's called Jason Mason and the World's Most Powerful Itching Powder. Kathryn talks to him about the elements of a good children's book, his time creating and presenting children's television and how he's been helping adults to conquer their fear of public speaking.