Sustainability is a pressing concern for people and governments around the world, but it is also an essentially contested concept that requires an understanding of the stakes, trade-offs, and complex politics at play. Sustainability: The Basics offers an accessible and interdisciplinary introduction to the concept, and discusses key questions such as: What are the core principles of sustainability? What are the key ethical considerations for questions of sustainability? How do we measure sustainability? What are the critical obstacles to achieving global sustainability? What happens when societies fail to observe principles of sustainability? Fully updated in its second edition, Sustainability: The Basics now includes coverage of the Sustainable Development Goals, a global range of case studies and explores the complex social dynamics of Earth system changes that affect our critical life supports. The second edition also proposes a new, "sustainable humanism" that animates much of our work to make a better, more humane world. As the world reels from the effects of the Covid-19 pandemic, this book is an ideal starting point for anyone who wants to know more about what we need to do to sustain civilization, humanity, and the world we live in.