Desertification is a little-understood term that aggregates several land degradation processes occurring in the arid regions of the world. The major processes are vegetation degradation, water erosion, wind erosion, salinization, and soil compaction. Water erosion is the principal threat to environmental stability in both arid and humid climatic zones. Land degradation is generally reversible unless damage is very severe or soils are shallow. Practices to control land degradation are widely available but are not put to use for many reasons. Absence of a food crisis in developed countries is one of the important reasons. A related reason is the perception that no real problem exists. A third reason is that degradation control is not cost effective, except for controlling salinity and compaction. It is time to change emphasis from reducing on-site damage to reducing off-site damage.