Abstract: Two persistent questions of enterprise law are raised and addressed: First, how does law matter to business practice? Second, how can we make law that stimulates economic efficiency? These questions are difficult to answer because of two important complementarities: the complementarity between areas of law within a country’s legal regime and the complementarity between law and other social environments such as markets and social norms. Over the course of the two-day conference, academics and practitioners from the U.S. and Japan in the areas of corporate law, securities regulation, labor law (including both employment protection law and labor union law), bankruptcy law, and tax law investigate the ways that enterprise law affects practice complementarily with markets and social norms. A key analytical framework is introduced, in which the business enterprise is viewed as an incentive mechanism among the four indispensable capital providers of the firm: management, employees, shareholders, and creditors. Only through close attention to the incentive bargain between these four players can optimal legislative design and economic efficiency be achieved.