A highly topical look at the formula that dominates economics, and why it has outlived its usefulness. Gross Domestic Product (GDP) is the world's economic health-check, an influential ranking of global prosperity. A rising number is manna for markets and keeps business buzzing; a falling one is a portent of doom for everyone. But, as science writer Ehsan Masood deftly shows, GDP can be unforgiving for those countries that cannot be—or choose not to be—measured by its rules. And it fails to measure much of what is really important to our lives. What began as a useful formula to assess a country's path to prosperity, has trapped societies and leaders into a system of measurement from which the world has to break free. We must, and this book shows how we can.