There are a growing number of general theories of contract law and of other doctrinal areas. These theories are vastly ambitious in their aims. This article explores the nature of these claims, and the motivations for offering such theories, while considering the challenges to success. It is in the nature of theorizing to seek general categories, including doctrinal categories, and to try to discover insights that hold across those categories. However, differences both within a doctrinal area and across legal systems undermine the case for universal and general theories. Also, unjustifiably general theories may distract us from developing properly contextual legal rules, and might even have the unintended effect of legitimating unjust rules.