Most educated readers know very little about the Holy Roman Empire beyond Voltaire’s quip that it was “neither holy, nor Roman, nor an empire.” For years, historians derided its institutions as archaic and ineffective. In this ambitious and challenging book, Wilson sets out to show that the empire was in fact quite successful. He points out that it survived for a millennium, from 800 to 1806, during which time it fostered a uniquely decentralized, consensus-based style of international decision-making. This system encouraged imperial subjects to adopt multiple identities: individuals could simultaneously be citizens of cities, principalities, and the empire. Imperial policies rested on compromises among all these groups, which could be slow and ineffective. Yet the system bolstered local rule and patronage networks, fostered a distinctive church hierarchy, oversaw legitimate courts, consistently collected taxes, and even produced institutional innovations, such as the first public postal service. Wilson concludes by reflecting that this multilevel system of governance, with its divided loyalties, might even serve as a model for today’s faltering EU.