Laws passed by Congress first appear as slip laws because they are published on thin pieces (slips) of paper. Congress passes two types of laws: private laws (pertaining only to an individual or a group) and public laws. Though both private and public laws have equal status, researchers are rarely concerned with private laws because of their limited applicability.
Public laws are numbered in consecutive order starting anew with each Congress. The citation for a new law is prefixed by the number of the Congress during which the law is enacted. For example, Public Law 96-272 (P.L. 96-272) was the 272nd law passed during the 96th Congress. It was passed in 1980 during the 2nd session of Congress.
Slip laws are bound in chronological order after the close of the session of Congress in which they are enacted.
A researcher can locate recent legislation through the following sources:
Online at the GovInfo website and in the advance sheets of the United States Code Congressional and Administrative News within a few weeks of passage. In addition, many topical loose-leaf services reprint legislation within a few days of passage (e.g., CCH's Congressional Index.)
Because laws (statutes) are published in chronological order, and each law may cover several topics, laws are "codified" - arranged into code volumes by topic or subject. These compilations are updated in a variety of ways to assure access to the latest revisions of the legislation.
The Official United States Code as published by the GPO. Also available in print in the law library.
United States Code Annotated, published by Thomson Reuters.
United States Code Service, published by Lexis.