Jonathan Haidt has spent his career speaking truth and wisdom in some of the most difficult places—communities polarized by politics and religion, campuses battling culture wars, and now the mental health emergency plaguing today's teens in many countries around the world.

In The Anxious Generation, Haidt shows how, between 2010 and 2015, childhood and adolescence changed shape. As teens traded in their flip phones for smartphones loaded with social media apps, online time skyrocketed, including time spent comparing themselves to countless others. Time spent interacting in person with friends and family plummeted, and so did mental health.

But this isn't just a story about technology; these profound changes are taking place against a backdrop of declining freedom and free play for children, as parents over-police every aspect of their children's offline lives, depriving them of the experiences they need most to become strong, independent adults.

In this book, Haidt makes a compelling argument that the loss of a play-based childhood and its replacement by a developmentally inappropriate phone-based childhood is a source of increasing mental distress among adolescents. The Anxious Generation examines the latest psychological and biological research to demonstrate four fundamental ways in which a phone-based childhood disrupts development—sleep deprivation, social deprivation, cognitive fragmentation, and addiction. Haidt offers separate, in-depth analyses of what is happening to girls and what is happening to boys, offering practical advice for parents, schools, governments, and adolescents themselves. Drawing on ancient wisdom and cutting-edge research, this eye-opening book is both a life raft and a powerful call to action.