This chapter frames the arguments of the book, defines terms, and outlines the story that will follow. In the eighteenth century, the Ottoman state and its Russian rival, through conflict and diplomacy, worked out a new system of regional international law. Ransom was abolished; soldiers became prisoners of war; some slaves gained new paths to release, while others were left entirely unprotected. These rules delineated sovereignty, redefined individuals’ relationships to states, and prioritized political identity over economic value. In the process, the Ottomans marked out a parallel, non-Western path toward elements of modern international law. This story has important implications, the Introduction argues, for our understanding of Ottoman history and the histories of both international law and slavery and abolition.