Like the other Onyx Court books, A Star Shall Fall owes a great deal to the people who assisted me in my research. In London, that included Mick Pedroli of Dennis Severs House, for advice on living in an eighteenth-century style; Eleanor John of the Geffrye Museum, for answers about house furnishings; Rupert Baker and Felicity Henderson of the Royal Society Library, for fetching out comet books and many dusty volumes of Royal Society minutes; Dr. Rebekah Higgitt and Dr. Jonathan Betts of the Royal Observatory, Greenwich, for assistance with the history of the observatory and horology respectively; Susan Kirby, Alan Lilly, and Mimi Kalema of Tower Bridge Authority, for letting me into the basement of the Monument very early on a Saturday morning; and Dr. Kari Sperring and her husband Phil Nanson, for touring me around Cambridge and even taking me punting.

I also needed a great deal of help via e-mail, on a variety of arcane topics. John Pritchard sent me a fabulous diagram of the Monument; Ian Walden advised me about local flora; Farah Mendlesohn was my go-to woman for Jewish history; Ricardo Barros of the Mercurius Company helped me figure out eighteenth-century dancing; Rev. Devin McLachlan did the same for eighteenth-century Anglican theology; and Dr. Erin Smith made the astronomy go. For information on Ottoman Arabic society, the Arabic language, and the nature of genies, I owe thanks to Yonatan Zunger, Saladin Ahmed, and Rabeya Merenkov. Sherwood Smith did the German translations for me, and Aliette de Bodard not only knew what iatrochemistry was, but could tell me how to say it in French.

The late-night conversations this time were with Adrienne Lipoma and my husband, Kyle Niedzwiecki, with an assist from Jennie Kaye. They very kindly let me talk at them endlessly about the book, and provided more than one useful suggestion.