Property exemplifies the virtues and the perils of the rule of law. As I will show, considerations of information cost call for a high degree of formalism in property law, compared to contract. The in rem aspect of property in particular has to be communicated to a large and indefinite audience. However, a subset of that audience can be expected to take hard-to-foresee kinds of advantage of the system of bright-line rules by finding loopholes. Such opportunism calls for limited intervention traditionally associated with courts of equity and embodied in equitable maxims, defenses, and