What are the Federalist Papers?
The Federalist Papers are a collection of writings written in 1787-1888 defending the merits of the Constitution. Written by some of the same men who wrote and debated the Constitution, they were originally published as 85 newspaper articles. The arguments made in the Federalist Papers were directed at the people who were deciding to vote for delegates to state ratifying conventions who would vote for or against the Constitution.
Why read the Federalist Papers?
Because the Federalist Papers are essentially a commentary about the Constitution written by the people who wrote the Constitution, they hold a lot of weight. If you want to understand America's foundings and law of the land, why not go straight to the source?