Property rights do many things; two of them are particularly useful. Property rights channel the productive output of property to its owner, which provides an incentive to invest in and use the property in a socially productive way. They also solve the problem of how to decide what the most productive use of property is, by conferring in its owner almost absolute discretion over how the property should be used. There are some circumstances, though, in which property owners are compensated for their investment in (and operation of) property but are denied discretion over how the property is to be used. Common carriers, for instance, may own their own trucks, buses, or trains, but they are not permitted to discriminate among potential customers. They must serve all comers. I call property regimes in which the discretion of property owners is so limited, regimes of “open access." In an open access regime, access to the property is open to all on a nondiscriminatory, but paid, basis. Open access regimes have received considerable attention of late in intellectual property, antitrust, and communications law literature for their potential to solve various problems presented by private control over important information resources. Intellectual property law in particular has been resistant to the suggestion of many scholars that the rights of intellectual property owners should be limited, through duration, reduction in the scope of rights, or reduced liability for producers of technology that can be used to increase dissemination of protected works. Communications markets – which have historically been subject to open access restrictions – are the site of considerable deregulatory activity, increasing the control enjoyed by providers of some communication networks. In the face of what they see as a regime that places too much discretion in the hands of owners of intellectual property and communications resources, many academics have suggested that the rights of remuneration and control typically combined in property rights be divorced to allow incentive-conferring compensation to flow to owners of these resources without granting them control over how those resources are used. This paper seeks to take a step back, to derive from established law the accepted bases for imposing open access rules on property rights. Although the open access landscape is pockmarked with unusual cases that were likely the result of purely political forces, most open access regulation has been surprisingly consistent over time and the proffered justifications even more so, suggesting some rational basis for the distinctions drawn by the law