'Water is a vital element for agricultural production and for economic development in general. However, the spatial and temporal distribution of water in Mexico restrains its use. Because of this distribution, it has been necessary to build a large infrastructure to capture, store, and allot this element among water users.' Around the world, countries that once promoted more government involvement in irrigation management are adopting new policies that do just the opposite, creating incentives for farmers to take over the management of operations and maintenance, while government agencies focus on improving the management of water at the main system level. Is this just another management fad; or will the pendulum that is now swinging toward greater management control by farmers soon swing back the other way, toward greater state control? This volume reports on four countries where the state's role in irrigation management has undergone fundamental change and where the result has been a much greater management role for farmers. These studies address the political antecedents of participatory irrigation management (PIM) policies, the process of implementing the policies, and the second-generation challenges of sustaining PIM. These experiences will prove useful to policymakers and irrigation professionals who are facing similar challenges in their own countries.