The story of Wolfgang Amadeus Mozart’s precocity is so familiar as to be taken for granted. In scholarship and popular culture, Mozart the Wunderkind is often seen as belonging to a category of childhood all by himself. But treating the young composer as an anomaly risks minimizing his impact. In this book, Adeline Mueller examines how Mozart shaped the social and cultural reevaluation of childhood during the Austrian Enlightenment. Whether in a juvenile sonata printed with his age on the title page, a concerto for a father and daughter, a lullaby, a musical dice game, or a mass for the consecration of an orphanage church, Mozart’s music and persona transformed attitudes toward children’s agency, intellectual capacity, relationships with family and friends, political and economic value, work, school, and leisure time.   Thousands of children across the Habsburg Monarchy were affected by the Salzburg prodigy and the idea he embodied: that childhood itself could be packaged, consumed, deployed, “performed”—in short, mediated—through music. This book builds upon a new understanding of the history of childhood as dynamic and reciprocal, rather than a mere projection or fantasy—as something mediated not just through texts, images, and objects but also through actions. Drawing on a range of evidence, from children’s periodicals to Habsburg court edicts and spurious Mozart prints, Mueller shows that while we need the history of childhood to help us understand Mozart, we also need Mozart to help us understand the history of childhood.