Sustainable development is the central challenge of the 21st century. How can human civilization continue to develop without destroying the natural systems on which it depends? Environmentalists tell us that capitalism is the problem because it feeds our self-interest. They tell us that we have to restrain ourselves and only consume what the Earth can sustain. Or governments must tell us what we can and cannot buy. This book uses the science of complex systems to explain why governments cannot deliver sustainability or happiness and how self-interest can be used to make society sustainable.