I have many debts, including, of course, to Kathleen Fasanella. I would like to offer particular thanks to Michelle Dawson for her comments on the manuscript and also for helping me to understand recent research on autism. Bryan Caplan offered useful comments on the manuscript, as did Autism Diva and Seth Roberts and my wife, Natasha. Parts of chapter 3 are drawn from much earlier conversations with Sahar Akhtar. Yana Chernyak offered help with some of the ideas in chapter 4. I thank Eric Lyon and Kiriana Cowansage for useful correspondence and ideas on music and aesthetics. The comments and feedback from my agent, Teresa Hartnett, and editor, Stephen Morrow, have been invaluable throughout. I have drawn on comments and conversations from many other people but I am not sure they all wish to be identified by name in this context, so I will offer them a very strong collective thanks.