Contracts provide managers and entrepreneurs an instrument of governance through which legally distinct parties can pursue transactions--from supply agreements to joint ventures—that the market has not standardized and priced. The willingness of common law courts to enforce contracts—with nothing more than evidence of an exchange—lubricates the economy with a valuable source of commitment that nourishes enterprise. Unfortunately, the social benefit of contract law is compromised by the opportunism that often results from the formalistic approach courts take to enforcing contracts, which is to construct contract terms to apply at all events unless expressly qualified. The party who bargained to receive performance is armed by law to sue even...