This book provides a sweeping, accessible, and deeply informed guide to the home we all share, showing us how we might best preserve the Earth's livability for ourselves and future generations. The book begins by setting the scene for our active planet and explaining how its location and composition determine how the Earth works and why it teems with life. It emphasizes the changes that are of concern to us today, from earthquakes to climate change and the clashes over the energy resources needed for the Earth's exploding population. It concludes with an extended exploration of humanity's prospects on a complex, protean, and ultimately finite world. It is not a question of whether the planet is sustainable; the challenge facing life on Earth—and the life of the Earth—is whether an expanding and high-consumption species like ours is sustainable. Only new resources, new priorities, new policies and, most of all, new knowledge, can reverse the damage that humanity is doing to our home—and ourselves. A sustainable human future, the book concludes, will require a sense of responsible stewardship, for we are not owners of this planet; we are tenants. Surveying the systems, large and small, that govern Earth's processes and influence its changes, the book addresses the negative consequences of human activities for the health of its regulatory systems but offers practical suggestions as to how we might effect repairs, or at least limit further damage to our home.