Many thanks, for all their help in lots of different ways to do with the creation of this book, must go to everyone at HarperCollins Children’s Books – particularly Nick Lake, Samantha Swinnerton, Kate Clarke, Elorine Grant, Manda Scott, Geraldine Stroud, Nicola Carthy and Ann-Janine Murtagh. Thanks must also go to: my illustrator, Jim Field, for co-creating these worlds; my children, Ezra and Dolly, who provided, as ever, very useful advice about being children, and also, in this case, about video games; my agent Georgia Garrett, who offered some late, but not too late, passionate suggestions; and Morwenna Banks, who calmly put up with the stuff she always has to put up with when I’m writing a book, even one this fun.