A National Security Letter (NSL) is roughly comparable to an administrative subpoena. Various intelligence agencies use NSLs to demand certain customer information from communications providers, financial institutions, and consumer credit reporting agencies under the Right to Financial Privacy Act, the Fair Credit Reporting Act, the National Security Act, and the Electronic Communications Privacy Act. Congress weighed several NSL amendments during the 113th Congress. The House passed one, H.R. 3361. The Senate failed to provide the three-fifths vote necessary for cloture on another, S. 2685. Yet in the end, the 113th Congress adjourned without enacting any of the proposed NSL amendments. The bills in the 113th Congress that would have amended the NSL statutes proposed adjustments in four areas: (1) the grounds for issuing an NSL; (2) confidentiality requirements and judicial review; (3) reports and audits; and (4) sunset and repeal. S. 1551 (Wyden), H.R. 3361 (House-passed), S. 1599 (Leahy), and S. 2685 (Leahy) would have defined more precisely the circumstances under which an NSL might be issued. Initially, the U.S. Court of Appeals for the Second Circuit and later the District Court for the Northern District of California concluded that the statutory secrecy and judicial review provisions relating to NSLs, read to their fullest, are inconsistent with the proscriptions of the First Amendment right to free speech and the principles of separation of powers. S. 1215 (Leahy), H.R. 3361 (House-passed), S. 1599 (Leahy), and S. 2685 (Leahy) would have amended the provisions in question roughly along lines suggested by the Second Circuit. In the past, Congress has counterbalanced expanded NSL authority with increased oversight mechanisms. For example, it directed the Department of Justice's Inspector General to conduct an audit of NSL authority from 2001 to 2006, and instructed the Attorney General to report to Congress annually on the extent of NSL use. Several proposals in the 113th Congress would have supplemented the existing mechanisms. S. 1215, S. 1551, and S. 1599 would have called for greater detail in the Attorney General's annual reports. H.R. 3035 (Lofgren), S. 1551, and H.R. 3361 and S. 1599 would have authorized recipients to issue public reports on the NSLs they receive. As an additional oversight tool, S. 1215 and S. 1599 would have returned all but two of the NSL statutes to their pre-USA PATRIOT Act form, effective June 1, 2015. The exceptions would have been the National Security Act NSL statute, which evokes few privacy concerns, and the sweeping, USA PATRIOT Act-born, Fair Credit Reporting Act NSL statute, which the bills would have repealed. This report reprints the text of the five NSL statutes as they now appear and as they appeared prior to amendment by the USA PATRIOT Act (to which form they would have been returned under S. 1125 and H.R. 1805). Related reports include CRS Report R40138, Amendments to the Foreign Intelligence Surveillance Act (FISA) Extended Until June 1, 2015, by Edward C. Liu, and CRS Report RL33320, National Security Letters in Foreign Intelligence Investigations: Legal Background, by Charles Doyle.