In late April of 1789, Sen. William Maclay of Sunbury, Pennsylvania, began his invaluable diary. Except for a few scattered notes taken by other senators and Vice President Adams, this diary is the only source of the debates on the Senate floor. Maclay, who had supported the ratification of the Constitution, quickly became an opponent of most of the Federalist agenda and has been classified as the first Jeffersonian Republican. His caustic, sometimes witty, and generally accurate diary stands just behind James Madison's notes from the Federal Convention as the most important journal in American political and constitutional history. Fortunately it has survived virtually intact.