David Walliams, hailed as the heir to Roald Dahl by The Spectator, burst onto the American scene with the New York Times bestseller Demon Dentist. Now the UKs #1 bestselling childrens author is back with this high-flying adventure about a boy and his grandfather, perfect for fans of Jeff Kinney and Rachel Renee Russell.Grandpa is Jacks favorite person in the world. It doesnt matter that he wears his slippers to the supermarket, serves Spam a la Custard for dinner, and often doesnt remember Jack ...