Appropriations Law and the Red Book One of our most used publications is our Principles of Federal Appropriations Law, otherwise known as the Red Book. This multi-volume treatise on federal fiscal law is an essential resource for anyone researching matters of appropriations law, and is used daily throughout the federal government. When there is a question about how federal agencies can use their appropriated federal funds, Congress and federal agencies can request that GAO provide appropriations law opinion or decision. You can search all of our published appropriations law decisions by keyword, date, agency, and other key criteria on our website. We also offer classes to federal employees on appropriations law, provide informal technical assistance, and have a variety of appropriations-related resources publicly available. Want More? Our recently updated bid protest and legal decision pages have additional resources, and straightforward, easy-to-understand explanations of our legal work. Check it out to search our legal resources, learn how to file a bid protest, and find guidance, training, answers to frequently asked questions, and more.