The Federalist Papers

In 1787 and 1788, an anonymous writer, Publius, urged the citzens of New York to ratify the proposed Constitution of the United States. There were 85 essays published in New York newspapers, and you can read all of them online, or search their full-text by going to the Avalon Project. The papers can also be read online at Thomas, a Library of Congress website for federal legislative information.
It wasn’t until 1818 that Alexander Hamilton, John Jay, and James Madison were identified in print as the authors of the Federalist Papers. As you can see from the Thomas site, there is still some dispute about the authorship of a few of the papers.
if you’re looking for original intent, the Federalist Papers are important source documents.