National Academies Press Offers Free Book PDFs
The National Academies created the National Academies Press (NAP) to publish the reports issued by the National Academy of Sciences, the National Academy of Engineering, the Institute of Medicine, and the National Research Council, all of which operate under a charter granted by the Congress of the United States. Annually, NAP publishes more than 200 books on an array of topics including science, engineering, health, and related policy.
PDF versions of books published by the National Academies Press are downloadable to anyone free of charge. The current catalog comprises more than 4,000 titles plus future reports produced by the Press.