The term “legislative history” refers to documents generated as a bill works its way through the legislative process. Even bills not enacted into law may have a legislative history. The number and kinds of documents varies greatly and may include the text of the bill (including introduced, amended, and reported versions); conference reports; committee reports; House and Senate debate; statements made by sponsors; committee hearings, prints, and documents; presidential signing statements; reports from congressional agencies (such as the Congressional Research Service and Government Accountability Office); news coverage; and post-enactment analysis. Finally, relevant documents might include all of these materials on related bills from past or current congressional sessions.
Historically, there has been no single comprehensive source for legislative history documents. Which source you used depended on the type of materials you were looking for, the age of the materials, and what format you required. While this is still true today, you will find that theProquest Congressional database comes close to being a comprehensive source for legislative history research and documents. And Congress.gov (replacing Thomas) is a free legislative information resource provided by the Library of Congress.