As the world population grows, so does the demand for food, putting unprecedented pressure on agricultural lands. At the same time, climate change, soil degradation, and water scarcity mean that productivity of many of these lands is deteriorating. In many desert dryland regions, drinking wells are drying up and the land above them is sinking, soil salinity is increasing, and poor air quality is contributing to health problems in farm communities. "Rewilding" the least productive of these cultivated landscapes offers a sensible way to reverse the damage from intensive agriculture. These...