The future is going to be largely what we design it to be. Will the future be one of continued challenges from shortages of water, depletion of finite material and energy resources, and degradation of the environment, or one of effective and efficient systems that bring about concurrent environmental and economic prosperity for societal benefit? The role of engineers and designers on all scales—molecular, products, processes, and systems—is going to be central and essential in determining what tomorrow will look like. Green engineering—engineering for sustainability—uses the same traditions of brilliance, innovation, and creativity, which are the legacy of the engineering disciplines, within the context and perspective of environmental, economic, and social benefit. This new application of engineering excellence to sustain-ability is among the most complex and important challenges faced by science and technology.