A debt of gratitude to Emily Bestler, Jason Kaufman, Ben Kaplan, and everyone at Pocket Books for their belief in this project.
To my friend and agent, Jake Elwell, for his enthusiasm and unflagging effort.
To the legendary George Wieser, for convincing me to write novels.
To my dear friend Irv Sittler, for facilitating my audience with the Pope, secreting me into parts of Vatican City few ever see, and making my time in Rome unforgettable.
To one of the most ingenious and gifted artists alive, John Langdon, who rose brilliantly to my impossible challenge and created the ambigrams for this novel.
To Stan Planton, head librarian, Ohio University‑Chillicothe, for being my number one source of information on countless topics.
To Sylvia Cavazzini, for her gracious tour through the secret Passetto.
And to the best parents a kid could hope for, Dick and Connie Brown . . . for everything.
Thanks also to CERN, Henry Beckett, Brett Trotter, the Pontifical Academy of Science, Brookhaven Institute, FermiLab Library, Olga Wieser, Don Ulsch of the National Security Institute, Caroline H. Thompson at University of Wales, Kathryn Gerhard and Omar Al Kindi, John Pike and the Federation of American Scientists, Heimlich Viserholder, Corinna and Davis Hammond, Aizaz Ali, the Galileo Project of Rice University, Julie Lynn and Charlie Ryan at Mockingbird Pictures, Gary Goldstein, Dave (Vilas) Arnold and Andra Crawford, the GlobalFraternal Network, the Phillips Exeter Academy Library, Jim Barrington, John Maier, the exceptionally keen eye of Margie Wachtel, alt.masonic.members, Alan Wooley, the Library of Congress Vatican Codices Exhibit, Lisa Callamaro and the Callamaro Agency, Jon A. Stowell, Musei Vaticani, Aldo Baggia, Noah Alireza, Harriet Walker, Charles Terry, Micron Electronics, Mindy Homan, Nancy andDick Curtin, Thomas D. Nadeau, NuvoMedia andRocket E‑books, Frank and Sylvia Kennedy, Rome Board of Tourism, Maestro GregoryBrown, Val Brown, Werner Brandes, Paul Krupin at Direct Contact, Paul Stark, Tom King at Computalk Network, Sandy and Jerry Nolan, Web guru Linda George, the National Academy of Art in Rome, physicist and fellow scribe Steve Howe, Robert Weston, the Water Street Bookstore in Exeter, New Hampshire, and the Vatican Observatory.