The Federalist, commonly referred to as the Federalist Papers, is a series of 85 essays written by Alexander Hamilton, John Jay, and James Madison between October 1787 and May 1788. The essays were published anonymously, under the pen name "Publius," in various New York state newspapers of the time.
The Federalist Papers were written and published to urge New Yorkers to ratify the proposed United States Constitution, which was drafted in Philadelphia in the summer of 1787. In lobbying for adoption of the Constitution over the existing Articles of Confederation, the essays explain particular provisions of the Constitution in detail. For this reason, and because Hamilton and Madison were each members of the Constitutional Convention, the Federalist Papers are often used today to help interpret the intentions of those drafting the Constitution.