After decades of stable or improving mental health among adolescents, a catastrophe occurred: in the early 2010s, rates of depression, anxiety, self-harm, and suicide among children rose sharply. Why? In this book, social psychologist Jonathan Haidt discusses the epidemic of mental disorders among young people that has swept across many countries around the world. The author explains the social consequences of children escaping into virtual worlds, why girls suffer from this more than boys, and uses examples to show how play and independent exploration of the real world help children grow into resilient adults. Haidt offers specific steps that parents, teachers, schools, technology companies, and governments can take to stop the epidemic of mental disorders and give children back their healthy childhood.