Also Shelved at the Middleton Reference Desk. It includes the text of the Constitution and Amendments in the front, and explains the powers and functions of each and every government agency, from the three main branches to the various agencies, departments, and quasi-official organizations. You'll save yourself time and frustration. If you need to do research on court cases, look here first to understand the federal court system.
Most agencies have descriptions of the types of documents they publish on their web pages.