Our society is a performance society. But what do we mean when we talk about "performance"? How did performance become an apparently objective, individual measure, and how have social relationships and feelings changed as a result? Why do people define themselves by their performance – or by what they and others think of it? Nina Verheyen vividly and enlighteningly describes how the understanding of performance has evolved and tells the story of an idea that shapes all our lives. She advocates for a historically informed and simultaneously new, more social definition of performance, which can be compellingly argued against optimization pressures, market mechanisms, and social inequality.