Throughout the world, customary rights in land are being replaced by for-mal systems of tenure, often devised to stimulate change in forms of agrarian production. With the demise of col-lectivism and the dissolution of many state-owned agricultural enterprises, privatization of rural land has gained legitimacy as a model for both empowering and'modernizing'a peasantry, for the theoretical aim of achieving greater sustainability of and efficiency in forms of resource use (Toye 1987). But, despite the rosy image of peasant rights being secured through private title, the moment of enclosure and privatization is more often characterized by exclusivity rather than equity. All too often, land is consolidated in the hands of a few, who use it less intensively and sometimes less efficiently than was the case prior to enclosure (Bromley 1992). To avoid the inequities and fragmen-tation that accompany privatization, some tenurial models have been devel-oped that would confer land rights on a community, whose members would bear responsibility for managing and husbanding its resources (Ostrom 1990). Far from allowing" open access" for anyone to anywhere," common prop-erty" systems, whether based on custom or innovation, are associated with a definable group, ideally a'community', for which having land'in com-mon'entails both rights in and responsi-bilities for definable resources (Bromley & Cernea 1989). 1 Community property, which, although often based on custom-ary rights may also be titled, is most ap-propriately distinguished not from'pri-vate'property, per se, but from individ-ual ownership, on the one hand, and state ownership on the other. One might suggest that the future disposition of the world's great agrarian regions will be influenced by whether community property-in its many forms-proves politically sustainable faced with its attractiveness for those in a position to benefit from its enclosure and individ-ualization. Quite apart from whether state, communal or private holdings tend to be more or less efficiently or sustainably managed, if land can be, it tends to be individually appropriated unless institutional and legal safeguards are put in place and the legitimacy of a given form of land holding is main-tained (North 1990). This paper ex-plores the legal, institutional and social conditions under which a particular system of common holdings becomes vul-nerable to enclosure and individualiza-tion: Group Ranches in Kenya. The conundrum of property is es-pecially acute for dryland regions for which the contradiction between equity and viability-and between achiev-ing scales of holdings ecologically large