560 International Organization This approach leads to two principal dimensions of variation in overseas investments expected to be associated with different levels of interstate conflict and the propensity for such investments to have been involved in colonialism. The first is the ease with which rents accruing to investments can be appropriated by the host country,or protected by the home country,by coercive means.Everything else being equal,the more easily rents are seized, the more likely the use of force by home countries.The second dimension is the difference between the net expected benefits of cooperation among home countries as compared with unilateral action by a single home country.This is a function both of the degree to which interinvestor cooperation facilitates monitoring and enforcing property rights to the investment and of the cost of organizing and sustaining such concerted action by home countries.All else being equal,the lower the net expected benefits of cooperation,the more likely are home countries to engage in unilateral action,including colonialism. Certain types of investments appear to have lent themselves more easily than others to protection by the unilateral use of force by home governments.This is especially true for investments with site-specific and casily appropriated rents, such as raw materials extraction and agriculture.For such investments,colonial control resolved inherent property rights problems that arose in its absence. This is not to say that these investments caused colonialism,for the reverse might have been the case-the greater security colonialism offered might have attracted disproportionate amounts of certain kinds of investments;it is, however,to argue for an affinity between certain cross-border investments and colonialism.I do not claim that these factors exhaust all explanation.Clearly geopolitical,technological,ideological,and other forces were important;but the sorts of differentiated economic variables discussed here often have been neglected in studies of colonialism.Further,their importance appears con- firmed by historical evidence. The first section reviews the long-standing dispute over colonialism and foreignt investment,reshaping it in more general terms.The next section goes on to redefine the analytical issues in the context of property rights and contractual problems inherent in cross-border investment and to explore the implications for the study of colonialism.The third section presents more specific hypotheses about the effects different sorts of overseas investments are expected to have on the attractiveness of colonial control (and vice versa)and about the likely distribution of types of investment among colonial and noncolonial countries.The fourth section examines rudimentary data about the relationship between different types of investment and different forms of rule, while the fifth section brings more qualitative historical evidence to bear on this problem.The final section summarizes the conclusions of this analysis and discusses its implications