This report is from The Union of Concerned Scientists. It presents seven “deception dossiers”—collections containing some 85 internal company and trade association documents that have either been leaked to the public, come to light through lawsuits, or been disclosed through Freedom of Information Act (FOIA) requests. Each collection of internal documents reviewed here reveals a separate glimpse of a coordinated campaign underwritten by the world’s major fossil fuel companies and their allies to spread climate misinformation and block climate action. The campaign began decades ago and continues today. The letters, memos, and reports in the dossiers show that company executives have known for at least two decades that their products—coal, oil, and natural gas—cause harm to people and the climate.