This volume is a must for anyone interested in the current state of the development of monetary theory as viewed by the community of most of the distinguished monetary economists. Both the work on monetary theory and the understanding of its importance have exploded in the last 20 years. This valuable compendium shows the enormous and detailed developments made recently. It highlights the problems in blending theory with institutions. It is a contribution of note. -- Martin Shubik, Yale University Monetary Economics has made great strides since the HANDBOOK OF MONETARY ECONOMICS, Volumes 1 and 2 was published. In Volumes 3A and 3B you will find surveys, written by leaders in their fields, of new work on foundations, the transmission mechanism, adaptive learning and expectation formation, optimal monetary policy, constraints on monetary policy, robustness in macroeconomics, monetary policy in practice, and much more, as well as applications to the latest crises. Every economist will want these volumes placed within easy reach on their bookshelf. -- William A. Brock, University of Wisconsin, Madison