Renowned British economist Diana Coyle traces the history of an artificial, abstract, complex, but crucial statistical indicator - GDP - from its predecessors in the 18th and 19th centuries. to its invention in the 1940s, the post-war "golden age" and today. The reader will learn why this standard tool for measuring the size of the economy was invented, how it has changed over the decades, and what its strengths and weaknesses are. The book explains why even the smallest changes in GDP can determine the outcome of elections and influence important policy decisions. In the final chapter, the author convincingly shows that GDP was a good indicator for the economy of the 20th century, but is increasingly less suitable for the economy of the 21st century, in which innovation, services and intangible goods play a decisive role.