This is unquestionably the most difficult book I’ve ever written. Time travel seems like such a useful thing until you have to confront the implications close-up. (Just say no to time travel. You think it will solve your problems, but in the end you have all the same problems, just much more tangled up with time.) I owe huge thanks to the late John M. Ford, whose GURPS Time Travel started me thinking about it in interesting ways, and whose personal conversation on the subject was invaluable. There were so many times when I really wanted to email him when writing Necessity but he has gone where email doesn’t reach. Death sucks. Read his books.

Ada Palmer was the person I could still pester with my queries and hesitations. She was unfailingly helpful, thought-provoking and wonderful throughout the process, and I am deeply grateful. This series wouldn’t exist without her. She was with me at the solar telescope in the Lowell Observatory in Flagstaff, and in Bologna. Read her books and listen to her music.

While tearing my hair out over this book I also had useful conversations with Evelyn Walling, Emmet O’Brien, Ruthanna and Sarah Emrys, Mary Lace, and Alison Sinclair. Emmet also put up with me while I was writing, which isn’t always easy. My son, Sasha Walton, insisted on dinosaurs and alien gods.

Lauren Schiller read the second draft overnight, which was both useful and reassuring. And she, Ada, Mack Muldofsky, Jon Singer and Jim Hannon put up with me while I was writing and travelling at the same time. I have the best friends.

After it was written it was read by Elaine Blank, Pamela Dean, Ruthanna and Sarah Emrys, Eric Forste, Steven Halter, Mary Lace, Marissa Lingen, Lydy Nickerson, Emmet O’Brien, Ada Palmer, Doug Palmer, Lauren Schiller, Sherwood Smith, and Sharla Stremski, for all of whose timely comments I am very grateful. Marissa Lingen and Emmet O’Brien also provided invaluable help with science.

The beautiful teahouse Camellia Sinensis of Montreal gave me a free sample of magic writing tea when I mentioned that was what I needed to get unstuck, and it really worked. Never underestimate the power of tea, or placebos either.

“You must change your life” is a quotation from Rainer Maria Rilke’s “Archaïscher Torso Apollos,” 1908.

My thanks as always, but never pro forma, to Patrick Nielsen Hayden, Teresa Nielsen Hayden, Alexis Saarela, Jamie Stafford-Hill, and everyone at Tor.

Books by Jo Walton

BOOKS BY JO WALTON

The King’s Peace

The King’s Name

The Prize in the Game

Tooth and Claw

Farthing

Ha’penny

Half a Crown

Lifelode

Among Others

What Makes This Book So Great

My Real Children

The Just City

The Philosopher Kings

Necessity

About the Author

ABOUT THE AUTHOR