Legislative history is the record of legislative activity by Congress during the drafting and passage of a bill into public law. It is used by courts for evidence of Congressional purpose or intent when the language of a statute is unclear. Courts sometimes also refer to legislative history in order to confirm their interpretation of a statute and you can also use it as background information to help you understand a statute that is unclear to you. You compile a legislative history by pulling together the documents that Congress produces during the legislative process. In most cases these documents are bills, hearings, committee reports, committee prints, floor debates and presidential signing statements. To understand legislative history research, you need a basic understanding of the legislative process. If you would like to review the process as well as find descriptions of Congressional documents go to HOW OUR LAWS ARE MADE. 

Two subscription databases are excellent resources for federal legislative history research.  HeinOnline's U.S. Federal Legislative History Library provides congressional reports, hearings, and documents for selected laws.  Congressional Universe indexes federal legislative histories and has links to the full text for some recent material.  Other items are available in microfiche (back to 1970).

THOMAS is a free government Web site that has legislative history materials back to the 1980s.  It includes bills, amendments, votes, and reports.