The history of timekeeping has always involved choosing or converting between various ways of representing time, a phenomenon called time pluralism. The Unsettled Clock: The Persistence of Time Pluralism explores time pluralism by documenting historical cases and examining its persistence in present. Drawing examples from medieval York, the Habsburg empire of early modern Europe, Renaissance astronomy, legal time in the US and UK before time zones were adopted, and the persistence of time pluralism in current atomic time metrology, this analysis offers a political and historical look into how timekeeping has been shaped, challenged, and manipulated.