Deep in a Cairo synagogue, an unexpected treasure was unearthed: the lost archive of the Fatimid Caliphate. Contrary to longstanding belief, Islamic Middle Eastern dynasties produced and preserved many documents — some of which were recycled as scrap paper by Medieval Jews and deposited in their synagogue. Rustow’s book explores this crucial lost archive and advances our understanding of documents as physical artifacts, showing how they can change our thinking about the medieval Islamic world.