Legislative changes are needed in the 1976 Tax Reform Act, which currently hampers the Government's ability to detect and prosecute criminals. The act's disclosure and summons provisions afford taxpayers increased privacy with respect to information they provide the Internal Revenue Service (IRS) and additional rights in summons matters; however, the disclosure provisons inhibit coordination between IRS and other Federal law enforcement agencies. Similarly, the summons provisions adversely affect IRS' ability to carry out criminal tax investigations. Senate bills 2402, 2403, 2404, and 2405 would significantly revise these sections of the Tax Reform Act, and GAO supports their overall thrust; however, Senate bill 2402 can be further refined to authorize a more effective disclosure mechanism and improve the balance between privacy concerns and law enforcement information needs. The selected record of the effects of the disclosure and summons provisions of the 1976 Tax Reform Act and a comparative analysis of 26 U.S.C. 6103,7609, 7213, and 7217 with Senate bills 2402, 2403, 2404, and 2405 are appended. (Author abstract modified)