The Economics of Information Technology is a concise and accessible review of some of the important economic factors affecting information technology industries. These industries are characterized by high fixed costs and low marginal costs of production, large switching costs for users, and strong network effects. These factors combine to produce some unique behavior. The book consists of two parts. In the first part, Professor Varian outlines the basic economics of these industries. In the second part, Professors Farrell and Shapiro describe the impact of these factors on competition policy. The clarity of the analysis and exposition makes this an ideal introduction for undergraduate and graduate students in economics, business strategy, law and related areas.