This book is based on real events but is very much a work of fiction. Many names and details have been invented.
I am most indebted to the marvelous German historian Ulinka Rublack for her celebrated nonfiction book The Astronomer and the Witch: Johannes Kepler’s Fight for His Mother. I initially read Rublack’s book simply to learn more about Johannes Kepler. A detail in Rublack’s book—a neighbor of Katharina’s asking to be dismissed from serving henceforth as her legal guardian—caught my heart and opened up this novel for me. I have not used that neighbor’s real name, Veit Schumacher, because his voice and life in this novel are wholly imagined.
The letters that appear in this novel are based on real letters. The language used in the depositions is largely imagined, the exception being the opening question used throughout, which is a straight translation of what is found in the trial records. That translation was done by Alex Bernhardt Beatty. Beatty provided numerous wise and nuanced translations of original material and authored the translations of the two Kepler letters.
The broader translation—that of Katharina Kepler’s world across language and time—has been done with the J. A. Underwood translation of Hans Jakob Christoffel von Grimmelshausen’s The Adventures of Simplicius Simplicissimus as a spirit guide.
I have never enjoyed working on a book as much as I enjoyed working on this one, even as it is a sad book, written during a distressing time. I owe my happiness in large part to the works I read as part of my research. Many articles and books kept me in good company, most notably: Reformation Europe: New Approaches to European History, Series Number 54, by Ulinka Rublack; Witch Craze: Terror and Fantasy in Baroque Germany, by Lyndal Roper; The Crimes of Women in Early Modern Germany, by Ulinka Rublack; Ideas and Cultural Margins in Early Modern Germany: Essays in Honor of H. C. Erik Midelfort, edited by M. E. Plummer and R. B. Barnes; Witch Hunting in Southwestern Germany, 1562–1684: The Social and Intellectual Foundations, by H. C. Erik Midelfort; Johannes Kepler and the New Astronomy, by James R. Voelkel; Florilegium: The Book of Plants, by Basilius Besler; Johannes Kepler: Life and Letters, by Carola Baumgardt; A Magical World, by Derek K. Wilson; The Holy Household, by Lyndal Roper; The Thirty Years War, by C. V. Wedgwood; Kepler, by Max Caspar, translated by C. Doris Hellman; Leonhart Fuchs: The New Herbal of 1543, by Klaus Dobat and Werner Dressendörfer; Opera Omnia, by Johannes Kepler, edited by C. Frisch; New Astronomy, by Johannes Kepler, translation and introduction by W. H. Donahue; Martin Luther, by Lyndal Roper; Fictions of the Cosmos, by Frédérique Aït-Touati; The Cheese and the Worms, by Carlo Ginzburg; Cardano’s Cosmos, by Anthony Grafton; and https://somniumproject.wordpress.com.
The records of Katharina’s trial are available for the curious here: https://archive.org/details/joanniskeplerias08kepl/page/n9/mode/2up.
A partial translation by Pamela Selwyn of Johannes Kepler’s defense of his mother is available here: http://www.keplers-trial.com/keplers-defence.pdf.
My editor, Eric Chinski, and my agent, Bill Clegg, both offered substantial and generous editorial guidance that helped me find this book’s gravitational center. Robert Rubsam and Katie Schorr were a tremendous help in locating research materials. Columbia University’s Hettleman Junior Faculty summer research grant provided essential support. Deborah Ghim’s insights and shepherding have also been invaluable. Spenser Lee’s early support of the book buoyed me. Rodrigo Corral designed the unforeseen and ideal cover. And I am grateful to the whole team at FSG, who not only helped me with this book, but have brought into being so many books that I love to read.