This volume contains papers in the broadly defined area of microeconomic theory presented to the International Economic Association Tenth World Congress in Moscow. A wide range of topics is represented - from the foundations of economic choice through strategic behaviour, multiple market interactions, and asymmetric information to applications in such diverse areas as the internal organization of firms, patent policy, product markets, and labour supply, finishing with a piece on the history of oligopoly theory. The collection strongly suggests that microeconomic theory is indeed thriving as a fascinating and useful central part of economic science.