The SPIEGEL bestseller finally available as a paperback. The economic thought models have conquered and dominate all other social sciences. Economists have also made the emotional well-being of modern humans their concern and developed a model that assumes every person thinks solely of themselves and their own advantage. This book examines how the originally harmless model became a trap. Sixty years ago, military personnel and economists developed a theoretical model of a person: a selfish being focused only on achieving their goals, on their own benefit, and on outsmarting others – a modern Homo oeconomicus. After its career in the Cold War, it was not retired but instead took over the everyday life of the 21st century. Stock markets are now driven by it, as are people. Frank Schirrmacher illustrates this.