The status quo doesn't work for millions of Americans, and the consequences of millions of failures are expensive for everyone else. There has to be a better, fairer, and more cost-effective way of helping people achieve success. That is what this book is all about. The United States now spends trillions of dollars on chronic disease, incarceration, educational failures, and lost productivity-among the many problems of the current system. Instead, this book argues for better, more targeted spending that could guarantee an opportunity-rich childhood for all. The "guardrails" of the title are the aspects of a well-functioning neighborhood that help children become thriving adults: good schools, well-funded libraries, safe streets and public spaces, quality health care, churches and other spiritual homes, and transportation and other public services. "Airbags" are timely interventions at the individual level that help avert lasting damage from bad events. Examples include drug treatment or psychological counseling for troubled young people. The United States can afford both better guardrails and airbags for kids to help them become healthy and productive adults who will be effective parents for the next generation. This book advocates a smarter social safety net that will catch kids heading in the wrong direction before they are harmed, and society will pay for those upstream investments and reap the benefits of healthier and more productive generations to come.