Most Americans never get past the Federalist. Nos. 10 and 51 (if any at all), but there’s a couple of things to keep in mind when reading arguably the most significant complimentary piece to the Constitution.
1. It was written as propaganda to get New York to ratify the Constitution.
Really, the entire history of New York’s delegation during the Constitutional Convention is hilarious in its pettiness: Governor Clinton sent John Lansing, Jr., and Robert Yates to the convention for pretty much the sole purpose of outvoting Hamilton; Hamilton got pissy and left, and by the time he returned Lansing and Yates left in a huff. And that’s why there’s only one signer for the state of New York.
New Yorkers, strong anti-federalist territory, were upset because they thought the Convention would just rework the Articles of Confederation; hyperbole galore erupted from all sides. So Hamilton proposed The Federalist to get federalist delegated into the Ratifying Convention, and sell the Constitution to the constituents.
2. John Jay was supposed to have played a much larger role
Hamilton first intended The Federalist to be a piece by New Yorkers for New Yorkers, so he first recruited John Jay (he also later considered William Duer and Gouverneur Morris, but nothing came of those), who would have written the pieces concerning the role of the foreign relations. Hamilton also brought in James Madison, both for his knowledge of the history of republics and confederations, and because Virginia was also anti-federalist territory. But Jay later in had a bout of what historians think was rheumatism in November 1787, and so the majority of the work fell on Hamilton and Madison.
3. A lot of these things were first drafts
Simply put, Hamilton and Madison didn’t have the time to make The Federalist into a grand political-philosophy book for the ages, to edit and revise as needed. Hamilton was already overworked as a lawyer, and sometimes he just had to hand one over to the printer as soon as he finished it (after Madison returned to Virginia, Hamilton churned out twenty-one essays in two months).
4. While there is still some dispute over who wrote which essay, the general consensus is agreed that:
Hamilton wrote 51: (Nos. 1, 6–9, 11–13, 15–17, 21–36, 59–61, and 65–85)
Madison wrote 26: (Nos. 10, 14, 37–58 and 62–63)
Jay wrote 5: (Nos. 2-5 and 64)
With Nos. 18-20 still in dispute between Madison and Hamilton.
Both Hamilton and Madison wrote lists before they died saying which papers they wrote, but both men were too kind to themselves. See the work of Douglass Adair for how the breakdown of the dispute between Hamilton and Madison’s papers were resolved.