For me, the most exciting aspects of communities are their dynamism and their power to effect change at levels ranging from individual purchases to global movements for social and environmental justice. Recently my studies have turned to such “communities of purpose.” For example, for more than three years now Diane Martin and I have been engaged with groups of people determined to make Walmart more environmentally sustainable. Self-selecting community members include Walmart executives and associates, key members of its supply chain, environmental activists, academics, and others. Uniting these diverse participants are shared goals of carbon neutrality, zero waste, and products that support the sustainable use of the earth s finite resources. So far these groups have achieved impressive results, helping Walmart to divert millions of tons of waste from landfills, radically reduce its use of fossil fuels, develop more sustainable products, and (true to Walmart’s mission) continue to profit, even in times of economic recession, with low prices to its customers. Explore walmartstores.