Prior to the passage of the Federal Register Act (F.R.A.) in 1935, there was no system of publication for federal regulations. Each agency had its own method for keeping track of its regulations, but contributed to no central system for notifying the public of the regulations. The F.R.A. required daily publication of agency regulations and other information of interest. When the Administrative Procedure Act (A.P.A.) was passed in 1946, it required public notification for participation in rulemaking.

To comply with these acts, the Federal Register system was developed. It is comprised primarily of the daily Federal Register (Fed. Reg.) and the annual Code of Federal Regulations (C.F.R.). These two publications provide an up-to-date version of agency regulations. Citation to the Fed. Reg. is to volume and page. Citation to the C.F.R. is to title and section.
To find an agency's regulations, use the C.F.R. The current edition of the C.F.R. is found on FDsys, LexisNexis, Westlaw, and BloombergLaw. It is also shelved on the 9th floor of the library; editions from earlier years are located in the Microform Room and in HeinOnline.
The C.F.R. is a codification of the current "general and permanent" regulations of the federal government. The C.F.R. consists of 50 titles that represent broad subject areas. The titles are divided into chapters, chapters into parts, and parts into sections. (The titles sometimes have a number corresponding to the placement of the agency's enabling legislation in the United States Code.)
The C.F.R. has its own print index called the CFR Index and Finding Aids, which is revised annually as of January 1. This volume contains a subject/agency index. In addition, it contains a list of agency-prepared indexes which appear in individual C.F.R. volumes; a list of C.F.R. titles, chapters, subchapters, and parts; an alphabetical list of agencies appearing in the C.F.R.; a list of acts requiring publication in the Fed. Reg.; and a table of laws and Presidential documents cited as authority for regulations currently codified in the C.F.R. Alternatively, use West's Code of Federal Regulations Index in print or on Westlaw.
Because the C.F.R. is updated only annually, the Fed. Reg. must always be used to determine if the regulation has been changed since the C.F.R. volume was last published. Copies of the Fed. Reg. are shelved on the 9th floor; microfiche copies of the Fed. Reg. from 1936 to date are in the Microform Room. LexisNexis, Westlaw, and Bloomberg Law update their CFR files regularly. The government updates an unofficial e-CFR daily.  The Federal Register Collection in HeinOnline goes back to the first volume in 1936. HeinOnline can be accessed through BEN.
Four types of documents are printed in the Fed. Reg.:
Presidential documents (usually either proclamations or executive orders);
rules and regulations;
proposed rules; and
miscellaneous agency notices.
The Fed. Reg. has its own monthly index which cumulates each year.
Updating regulations to the present day is critical. To update the C.F.R., use the List of CFR Sections Affected (L.S.A.), a monthly publication. L.S.A. issues are shelved with the current C.F.R. volumes. L.S.A. cumulates annually into four issues that cover all 50 C.F.R. titles according to the following schedule: Titles 1-16 as of December; Titles 17-27 as of March; Titles 28-41 as of June; Titles 42-50 as of September
First, use the annual cumulation of the C.F.R., then update that with the latest monthly issues of the L.S.A. (which cumulate the months since the effective date of the annual). Finally, use the "CFR Parts Affected" in the latest available issue of the Fed. Reg. This table cumulates changes appearing in all Fed. Reg. issues for that month. To summarize, update the C.F.R. by checking the following:
Annual L.S.A.
Latest monthly L.S.A. issue
Latest daily issue of the Fed. Reg. (current month and any month for which there is not coverage by the L.S.A.)
The need for using the annual L.S.A. issue always depends on whether a new C.F.R. title has been published since the last annual L.S.A. was issued. Follow the dates provided on the outside covers and tops of each page. The Shepard's Code of Federal Regulations Citations shows references to regulations, proclamations, executive orders, and reorganization plans in federal and state court decisions, selected law journals, and legal texts since 1977. This citator does not update the regulations themselves. KeyCite can be used on Westlaw to identify citing cases and secondary sources.