Economists like to say that there is no such thing as a “free lunch” whenever we move our social arrangements in a new direction. According to this kind of thinking, a price will inevitably be paid for addressing big, society-wide problems such as global warming. This book takes a contrary view—resolving the problem of global warming and moving to a more spatially compact form of human settlement will generate a durable and widespread prosperity and improvements in the quality of life. In short, fixing global warming will be a ‘free lunch.’ We will all end up being better off independently of any gains to the climate or the natural environment. The turn to clean energy will set off an unprecedented economic boom driven by innovation in energy conservation, production, and distribution and by increased high density urban living and the private and public construction that will go with it. Unlike the economic expansions of recent decades, growth induced by a shift to clean energy and compact living will truly lift all economic boats. Turning to compact green living and freeing ourselves from the environmental tyranny of fossil fuels will set off an investment boom of a new kind— a good boom that will help cure some of our most intractable social and environmental ills. This combination of ideas is the unique and original contribution of this book. If moving toward stabilizing climate becomes a reality—and in all likelihood it will despite the convoluted political path we are currently taking toward limiting greenhouse gas emissions—we will soon start unhooking ourselves from fossil fuels. Not to do so would be an exercise in mindless naivety of historical proportions. The idea of “peak oil” predicts that we will have to unhook ourselves from fossil fuels anyway by the end of this century, so why not do it sooner rather than later? If we have the insight and fortitude to pursue clean energy today rather than fifty years from now, we will save trillions of dollars that would otherwise drain away into the bank accounts of Arab oil aristocrats and petroleum dictators. These funds instead could be diverted to our own economy through the creation of a clean energy industry and a high-density, compact form of urban life. Because the nuclear energy option is so costly and publicly viewed as too dangerous, the sensible path is to replace fossil fuels with solar and wind energy and pursue the abundant opportunities available to us for energy conservation, the cleanest and greenest energy of all. Given ‘peak oil,’ the pursuit of fossil fuel carbon capture technology that injects carbon back into the earth from whence it came would seem to be a huge waste of money. Why try to fix something we are running out of anyway? The kinds of economic incentives and public spending that will push us toward clean energy will simultaneously move us in the direction of compact living. Greater spatial compactness will not only reduce the pace of climatic warming, but it will help contain the human footprint on the earth’s surface and leave more space for nonhuman nature. This, along with less global warming, will in turn help forestall the mass species extinction event that appears to be in the making. The inevitable trend toward compact living can either be embraced because it is both good for the global environment and a decent way to live, or it can be resisted in a quest to preserve the traditional low density suburban way of life. The choice is ours individually and politically. If we choose to embrace compact living, I believe we will be rewarded with an economic boom and unprecedented prosperity. Saving the planet for ourselves as well as nature will in the end be both an economic and an ethical ‘free lunch.’