In a large number of developing countries, policy makers and researchers are increasingly aware of the conflicting demands on water, and look to agriculture to be more effective in its use of water. Focusing on both irrigated and rain-fed agriculture, this book gives a review of the limits and opportunities for improving water productivity in crop production. It demonstrates how efficiency of water use can be enhanced to maximize yields. The book represents the first in a new series of voumes resulting from the Comprehensive Assessment of Water Management in Agriculture, a research program conducted by the CGIAR's Future Harvest Centre, the Food and Agriculture Organizaion of the United Nations and partners worldwide.