Housing systems in the cities of the developing world still largely operate outside financial regulation, planning codes, and "lawyers' law." To integrate squatter settlements into the official legal and planning system of cities in the developing world, governments have engaged in an unprecedented scale of land titling of these areas, claiming that their legalization facilitates the provision of utilities, makes land markets more transparent, and increases municipal tax revenue. While planning scholars and economists have been quick to evaluate the outcomes of these policies, it is poorly understood why particular communities enter the legal system and others remain outside. This doctoral dissertation research examines land titling processes in Brazil, a country with a highly active civil society, some of the most progressive housing rights laws in the world, and growing access to legal information. The project seeks to identify the driving factors behind initiation and negotiation of land titling in the informal settlements (favelas) of Rio de Janeiro and Recife, Brazil from 1990 to the present. The research uses both qualitative and quantitative methods to detail the land policymaking process in these cities. A multiple regression analysis of data from property registries will be employed to estimate the association between titles issued and contextual variables including location, past public investment in the area, and age of favela. This will be followed by a qualitative study of the incentives driving communities to approach planning offices and demand inclusion into the legal and planning regime. The application of social network mapping will clarify how information on regularization is disseminated and which types of favelas are most susceptible to legalization programs. The demand for titles will be explored in interviews with community members while participant observation during negotiations between residents and planners will illuminate which informal land claims are legitimated. Findings from this project will be summarized into articles -- both in Portuguese and English -- and published widely in print and Internet media in both countries. Presentations will be made to professionals in the American Planning Association and the Brazilian Institute of Urban Law (Instituto Brasileiro do Direito Urbano). Information will ultimately be presented for policy formulation to the Land Regularization Offices of Rio de Janeiro and Recife, various civil society groups, and agencies that fund land-titling programs. This award was co-funded by NSF's Office of International Science and Engineering.