This work uses recent developments in the theory of incomplete contracts to analyze a range of topics in organization theory and corporate finance. Beginning with a general model of the firm, Hart analyzes in greater depth the financial structure of firms, debt collecting and bankruptcy. Oliver Hart is a leading researcher in this area, and these Clarendon Lectures are an important contribution to contact theory. The work will be of interest to teachers, graduate students and advanced students of microeconomics, the theory of the firm, industrial organization, and finance.