This volume presents the work of leading scholars in the areas of aggregation, efficiency, and measurement, covering both theoretical and empirical aspects of the field. Among the topics included are new results concerning aggregation of technical efficiency, properties and estimation of directional distance functions, sources of productivity growth in U.S. manufacturing, extensions of Data Envelopment Analysis (DEA) models, the relative efficiency of economies with and without intellectual property rights, and the determinants of successful mergers. "Bob Russell has made fundamental contributions to the topics that constitute this volume’s title—aggregation, efficiency, and measurement. Although dealing with a wide range of economic phenomenon, including Pareto optimality in overlapping-generations economies, mergers in a principal-agent model, innovations and endogenous growth, and productivity growth in U.S. manufacturing, issues of technical or allocative efficiency feature prominently in all of the contributions to this volume in his honor. The high quality of this collection not only a fitting tribute to Bob Russell, but also a valuable resource for other scholars working on these issues." John A. Weymark Professor of Economics Vanderbilt University.