This book provides a comprehensive overview, in the form of eight long essays, of the evolution of monetary theory over the three-quarters of century, from the time of Keynes to the present day. The essays are originally based on lecture notes from a graduate course on Advanced Monetary Economics offered at York University, Toronto, written in the style of academic papers. The essays are mathematical in method but also take a historical perspective, tracing the evolution of monetary thought through the Keynesian model, the monetarist model, new classical model, etc, up to and including the neo-Wickesellian models of the early 21st century. The book will be an essential resource for both graduate and advanced undergraduate students in economics, as well as for individual researchers seeking basic information on the theoretical background of contemporary debates.