Many people contribute to the making of a book, but there are a few I would like to single out for heartfelt thanks. Dr Susan Buratto was incredibly generous, giving up her free time to educate me on the intricacies of mental health provision in the US criminal Justice system and beyond. Many of the characters and locations featured in this book sprang to life during our unconventional tour of Chicago. Back in the UK, Dr Lisa Barkley was equally generous and insightful – thanks to her I now have a much greater understanding of child psychology in general and distancing techniques specifically. I would also like to thank all the great people at Michael Joseph, especially Chantal Noel and Rowland White, who has been an outstanding editor and guide on this book and many others before it. Thanks must also go to my amazing agent, Hellie Ogden, for being a brilliant sounding board, inspiration and friend. Finally, my deepest thanks and love to Jennie, Chloe and Alex, for encouraging (and enduring) me as Kassie came to life. Chloe, I’m sorry the heroine isn’t called Ruby, as we’d discussed, but, hey, that’s the editorial process for you.