Misinformation is one of the twenty-first century's greatest challenges, a peril to democracy, peace, science, and public health. Yet we lack a clear understanding of what makes misinformation so potent and why it can spread so rapidly. In Falsehoods Fly, a leading cognitive scientist and philosopher offers a new framework for recognizing and countering misleading claims by exploring the ways that information works-and breaks down. Paul Thagard examines the dangers of misinformation on COVID-19, climate change, conspiracy theories, inequality, and the Russian invasion of Ukraine. He argues that effective responses to these problems require understanding how information is generated and spread. Bringing together empirical findings about the psychological and social mechanisms that drive cognitive errors with philosophical accounts of critical thinking, Thagard develops an innovative theory of how we gain information. Grasping how the generation and transmission of knowledge can fail helps us find ways to repair it and provides tools for converting misinformation into facts. Offering a deep and rich account of the nature and workings of information, Falsehoods Fly provides practical, concrete strategies to stop the creation and spread of misinformation.