CRS report – From Slip Law to United States Code: A Guide to Federal Statutes for Congressional Staff, May 2, 2018.

“This report provides an overview of federal statutes in their various forms, as well as basic guidance for congressional staff interested in researching statutes. When a bill becomes a law, the newly enacted statute may amend or repeal earlier statutes or it may create a new or “freestanding” law. Either way, these new statutes are first printed individually as “slip laws” and numbered by order of passage as either public laws, or less frequently, private laws. Slip laws are later aggregated and published chronologically in volumes known as the United States Statutes at Large (Statutes at Large). Statutes of a general and permanent nature are then incorporated into the United States Code (U.S. Code), which arranges the statutes by subject matter into 54 titles and five appendices. Statutes may be updated and published as amended public laws. As the statutes that underlie the U.S. Code are revised, superseded, or repealed, the provisions of the U.S. Code are also updated to reflect these changes. In these instances, the authoritative language remains the enacting statute, or the “base law.” However, some titles of the U.S. Code have been passed into “positive law,” meaning the law exists as it does in the U.S. Code and the title itself is the authoritative language. In these instances, it is the U.S. Code sections that are revised, superseded, or repealed, as the underlying statutes have all been revoked. In arranging statutes by subject rather than date, the U.S. Code may be more convenient to search than the Statutes at Large. Moreover, the Office of the Law Revision Counsel publishes tools known as “Tables,” to assist researchers in locating statutes, as well identifying statutes that may have been amended, omitted, transferred, or repealed. Nevertheless, certain laws are not added to the U.S. Code, such as laws appropriating funds, and thus researchers will often need to search laws in the other forms discussed herein.”