There are three published versions of the federal code, each organized by the same scheme of 50 numbered titles, each corresponding to a particular topic, e.g., Title 26 is the Internal Revenue Code. Each version is searchable by a subject index or a table of "Popular Names." The annotated versions also provide an index in each title.
Usually the "real-life" researcher will not have access to more than one version of the U.S. Code. Employers will generally own one of the annotated versions. Law school libraries may have all three. For currency and access to annotations, U.S.C.S. or U.S.C.A. are the best choices; however, according to the Bluebook it is necessary to consult U.S.C. to obtain citation information. Since each annotated version may contain references to sources which do not appear in the other, the student researcher may wish to consult both if available.
A number of Web sites contain all or parts of the United States Code (unannotated). Use caution as to their currency and look for the site's instructions on finding current updates. Some reliable sources of the U.S.C. are: