This book presents a theory of the firm based on its economic role as an intermediary between customers and suppliers. Professor Spulber demonstrates how the intermediation theory of the firm explains firm formation by showing how they arise in a market equilibrium. In addition, the theory helps explain how markets work by showing how firms select market-clearing prices. Models of intermediation and market microstructure from microeconomics and finance shed considerable light on the formation and market-making activities of firms. The intermediation theory of the firm is compared to existing economic theories of the firm including the neoclassical, industrial organization, transaction cost, and principal-agent models.

"Market Microstructure provides a rich new theoretical analysis of the role of firms in markets. It argues convincingly that by acting as intermediaries, firms can alleviate the problems of adverse selection, moral hazard, and high search costs, and can encourage valuable investment. Using elegantly simple models, this book offers deep new insights into why firms emerge and how markets function." Paul Milgrom, Stanford University

"Dan Spulber has been among the foremost contributors to the recent research on the role of firms as intermediaries (i.e., as middlemen). Different researchers have focused on differing roles for the firm, including reducing costs due to asymmetric information, search and matching, adverse selection, transactions costs, and agency. His new book provides a clear presentation of these developments that is outstanding for its breadth and depth, and for the order and organization he brings to a challenging topic." James Friedman, University of North Carolina, Chapel Hill

"Spulber's book provides an innovative and comprehensive look at two important issues--the formation and boundaries of firms and the microstructure of markets. This book does an excellent job of combining different models in a unified approach to studying firms and markets. I believe it will be an excellent text for students of this subject. " Chaim Fershtman, Tel Aviv University