There is an understandable tendency these days to be pessimistic about the future. To be sure, a planet of 10 Billion or more, with signs of serous climate change, severely constrained availability of water and food, and limited success tackling global poverty, to name a few, are not trends that inspire confidence. As the planet continues its high-speed charge towards urbanization, it remains to be seen whether this new global era will usher in an expanded capacity for solving these many challenges, or simply exacerbate them and make them intractable. Thus, how cities and urban life are designed and planned may be the single most important task ahead. The book you are about to read, and the insights, knowledge, and case examples it offers, will help steer the way. It posits that sustainability needs to be the ultimate goal for everything we do from here on; that it is no longer something optional, no longer simply lofty language but an essential lens and metric against which we must judge how well we are doing. You will need the depth of understanding and knowledge the editors and chapter authors so expertly provide here, but you will also need to be inspired, to be hopeful, and optimistic that your work in the future can make a discernible and significant difference.There has been a broadening of the city planning agenda and an increasing recognition that cities must consider many different challenges immediately and sustainably that is also helpful. Along with sustainability, there is a suite of complementary words that now make up the language of planners, urban designers, and managers. Resilience has emerged as one such potent word and an aspiration in a world where disasters such as Hurricane Sandy will become more common and cities will become first responders in periods of drought, heat waves, and disease outbreaks. The news is good here, as foundations like the Rockefeller Foundation with its 100 Resilient Cities Initiative are significantly elevating the profile and importance of resilience, and the tools available for advancing urban resilience, and cities, from New York to Rotterdam to Dhaka, are re-thinking the ways in which they occupy and inhabit their space. This suggests that these new adaptive strategies and, more profoundly, new modes of adaptive urban life will provide the means and confidence to meet 21st Century challenges head on. —Timothy Beatley, University of Virginia