This book explores the theory of political representation as articulated by the fourteenth-century Italian thinker, Marsilius. It combines historical research on Marsilius with an analysis of the contemporary theory of representative democracy. Modern theorization of political representation identifies the relation between the represented and the representative as a central theme. In order to assess how a representative system can reasonably be expected to operate for the benefit of the whole people, political representation must be understood through a comprehensive conception of the political process as a whole. To this end, Marsilius provides us with a perspective from which to examine the philosophical foundations of political representation and to reconsider the nature and significance of political representation - that is, an understanding of political representation in terms of the transfer of power. This book suggests that in modern democratic societies where the people effectively cease to be a political agent and their formal authority becomes increasingly notional, Marsilius' conception of political representation, which rejects the depoliticisation and deauthorisation of ordinary citizens, has much to offer. It can, in principle, offer a coherent alternative approach to building political representation as an effective scheme of public action for all.