To the extraordinary team at Little, Brown Books for Young Readers, all my thanks. I’m particularly grateful to my editor, Hannah Milton—for taking this journey with me, showing infinite wisdom, grace, and patience, and being as much of a Mindhunter fangirl as I am. Much appreciation to copyediting wizard Anna Dobbin and editorial assistant Ruqayyah Daud. Thank you to Janelle Barone, whose artistic work on the cover is an absolute knockout. Deep gratitude to the marketing and publicity team at LBYR, especially Siena Koncsol and Bill Grace, for getting this book into readers’ hands. Many huge thank-yous to Hannah Koerner and the LBYR subrights team for their incredible hard work bringing this story to the world.

I’d like to acknowledge and give thanks to David Colón-Cabrera, who provided invaluable feedback around representation and encouraged the manuscript’s improvement. I’d like to thank Shanese Mullins from LBYR for her excellent input. I’d also like to thank Pam Gruber, who first championed this book.

Hugs and thanks also to Jodie Webster, Sophie Splatt, and Eva Mills at Allen & Unwin for your awesome support, always, and for everything you’ve done to bring Emma, Travis, Kristin, and Simon to readers in Australia.

Speaking of readers, this book would be nothing without you. High fives to my newsletter mates and to every supportive friend, reader, blogger, and booktuber who has connected with me online, especially on Twitter. You’re awesome, and I thank you from the bottom of my heart. I pray you’re never forced to listen to Simon recite Byronic poetry.

This book was first conceived on a winter writing retreat in 2018, when I said, “I want to write a YA serial killer thriller,” and C. S. Pacat said, “That sounds amazing.” During long evening phone calls and frenetic brainstorming sessions, she has been the colleague who has kept me focused, inspired, and (mostly) sane. This book would not have been written without her unstinting support and friendship, and I am forever grateful.

When I needed ideas and advice (OMG, so much advice) and time and quiet space to complete the book, Amie Kaufman gave me all those things and more. She is a gem. Amie, all the love to you and your fam.

I’m deeply grateful to Amanda for getting as excited about serial killers as me, and sharing resources, podcasts, and ideas. I’d also like to thank Jay Kristoff for his advice and Fist-Bumps of Encouragement, and for letting me borrow his wife’s true-crime brain from time to time.

Everyone should have friends like Eliza Tiernan and Sarah Mayberry, who read the manuscript and declared it good and offered incredible insight. Thanks also to Liz Barr, who encouraged me to make Simon a real boy. Thank you to Kate Armstrong for explaining about Washington traffic, among other things. Thank you to Emma Viskic and Sulari Gentill for crime-fiction wisdom. I’m extra grateful to Jodi McAlister for adding to my store of knowledge about fairy princes.

I want to thank all the other members of the House of Progress, including Nicole, Lili, Peta, Ebony, Dave, Will, Kate, and Skye—I’d never have done this without your collective help. I’d also like to thank the women of the Vault, and I send lots of love to Fleur, Rachael, Nic, Gabrielle, Trin, and Bec. Thanks to other Australian writing compatriots, especially Angela, Kylie, Izzie, Alison, Nova, Simmone, Emily, Cate, Kelly, and Michael. I’ve probably left some people out, sorry—but friends, I see you, and I appreciate you every day.