Past and Present Agrarian Reforms in a Neoinstitutional Perspective - In this last decade agrarian reforms have been being in the political agenda of many countries, from Brazil to South Africa, from the Philippines to Colombia and to most transition economies. However, economists have not yet set up a sound theory of agrarian reforms, a systematic framework that one can rely upon to analyse land property rights and the economic effects of their redistribution among the population. This paper looks into some dimensions of agrarian reforms. A first part briefly introduces some history, politics and political economy of agrarian reform processes. A second part deals with the microeconomics of
agrarian reforms over time, that is the economics of property rights. In particular, it emphasizes that the new institutional economics, taking into account for market imperfections, provides scholars with a new agrarian reform paradigm: agrarian reform is not just land expropriation and redistribution but regulations of share cropping and leasehold contracts as well. This is a remarkable further step with respect to the classical orthodox theory, that takes institutions as exogenously given and assumes economic agents unresponsive to their structure.