Humanity is racing to find designed solutions to our environmental crisis. But what if designing itself was the cause of the crisis? This book argues that design, including 'sustainable' design, is at the heart of our crisis of unsustainability. Only when design's complicity in this crisis is understood, can sustainable human environments be conceived. Using the work of the controversial philosopher Martin Heidegger, this book constructs a radically different understanding of the design process. With this understanding, design in modernity is shown to be the engine of consumption of the Earth. Ironically, the conviction that that we can find designed solutions to our crisis of unsustainability may be the real danger facing the Earth. For those interested in design and design theory, this book offers a fundamentally different account of the design process. For those interested in Heideggerian thought, this book uses design to explore the 'positive role' of consciousness hinted at, but rarely investigated, in Heidegger's work. For those concerned about our crisis of unsustainability, this book offers a new way to conceive the forces accelerating the crisis.