Congressional reports are the written reports that accompany a bill from committee to consideration on the floor of the House or Senate. Congressional reports will explain the bill proposal and its intended effects in some detail. A House report and a Senate report may be available for each enacted law. Reports are assigned separate sequential numbers within each chamber (H.R. Rep. No. 97-8, S. Rep. No. 97-8).
The first number in the citation refers to the congressonal session. In the example, both the House report and the Senate report came out of the 97th session (1981-1982) of Congress. If the House and Senate pass bills that have significant differences, the bill may be sent to a conference committee to be reconciled. That conference committee may issue a conference report (H.R. Conf. rep. No. 97-8).
Committee reports are often considered to be the most important source of legislative intent for two reasons--authorship and content. First, the reports are authored by, and therefore contain the views of, multiple members of Congress. Second, the reports usually include not only the text of the recommended bill, but also the committee's findings and recommendations, the bill's legislative history, and a section-by-section analysis of the bill text.
Conference committee reports are of particular value because they are authored by members of both chambers, review the text of and the reasons for the compromise bill, and are issued closest in time to the passage of the law.
Congress.gov: 93rd Congress (1973) to present
Library of Congress (A Century of Lawmaking): U.S. Serial Set, selected reports, 23rd Congress (1833) to 64th congress (1917); American State Papers, selected reports, 1st Congress (1789) to 25th Congress (1839)
HeinOnline: American State Papers (under Other Related Works in the U.S. Congressional Documents Library), selected reports from 1st Congress (1789) to 25th Congress (1839)
Lexis: 101st Congress (1990) to present (selected coverage 101st and 102nd Congresses)
ProQuest Congressional: U.S. Serial Set, selected reports, 1st Congress (1789) to present; House and Senate Reports, selected reports, 101st Congress (1989) to present
ProQuest Legislative Insight: Selected, 71st Congress (1929) to present; access Legislative Insight via the law library landing page
Westlaw: 101st Congress (1990) to present, selected committee reports from USCCAN from 80th Congress (1948) to 101st Congress (1989)
USCCAN (United States Code Congressional and Administrative News) (KF51.U45): Selected, excerpted reports in Legislative History volumes, 77th Congress (1941) to present
In addition to the sources above, conference committee reports are published in the Congressional Record three calendar days before consideration unless the requirement is waived. The Debates tab lists Congressional Record resources.