The Federal Register is a daily publication of the goings on in all the Administrative Agencies in the United States. It is arranged chronologically and its pages are numbered sequentially. It contains newly published regulations, proposed rules, notices and presidential documents. The Federal Register was begun in an effort to bring transparency to administrative agency operations and efforts. Administrative agencies affect many aspects of American life and the American public had a right to know about the rules that were both in effect and the ones being proposed and to be able to easily comment on them and have their voices heard. The Federal Register Act was passed in 1935 and the first issue of the Federal Register was published on March 14, 1936.
There are many places you can find the Federal Register. The MacMillan Law Library maintains the Federal Register print, but if you are like most people and prefer electronic access, you have multiple places for access. Both GovInfo (produced by the federal government) and Federal Register.gov (produced by the National Archives) have Federal Registers available dating back to 1994. The Agency websites themselves are another good place to look. Lexis has Federal Registers dating back to 1980 and both Westlaw and Hein Online have Federal Registers dating back to its inception in 1936.