A legislative history includes the discussions and documents (such as committee reports, hearings, and floor debates) surrounding and preceding the enactment of a law. While a legislative history has special significance in Law, any historian, political or social scientist may benefit from tracing the chronology of a proposed bill to its ultimate passage form.
If you're lucky, a legislative history may already have been compiled for a given law. Here are possible sources:
The CIS index to publications of the United States Congress [Mugar Reference X Z 1249 F70] abstracts all congressional hearings and prints, arranged by committees; yearly bound volumes index publications by subject, document numbers, bill title, and names of persons involved.
The Legislative History volume tracks the movement of a bill through Congress. Mugar Memorial Library has the full-text of these publications on microfiche in cabinets in the Current Periodicals Area, arranged by CIS document number. When you find the hearing or committee print you want, also note its Superintendent of Documents (Sudoc) call number (number beginning Y4). The Boston Public Library is our local depository library for Government documents, and arranges its paper collection by Sudoc number.