Original meaning
Originalists of all stripes cite "The Federalist Papers". It is fairly tenuous to suggest that this represents a good source for the original "intent": after all, Alexander Hamilton, who wrote the majority of those essays, was absent for the greater part of the Philadelphia Convention, and John Jay did not attend it at all. However, James Madison, the principal framer of the Constitution also wrote a substantial amount of "The Federalist Papers". Also, to suggest Hamilton and Jay's absence from the convention implies their ignorance as to the Constitution's original meaning is demeaning to those two men and inaccurate. The collected anti-Federalist papers, of course, will be no use at all to a person searching for the original "intent" of the framers. However, as evidence of how a reasonable person at the time would have understood the words of the Constitution, "The Federalist Papers" and the anti-Federalist essays are evidence of direct relevance.
Alexander Hamilton
Hamilton recruited John Jay and James Madison to write a series of essays defending the proposed Constitution, now known as "The Federalist Papers", and made the largest contribution to that effort, writing 51 of 85 essays published (Madison wrote 29, Jay only five). Hamilton supervised the entire project, enlisted the participants, wrote the majority of the essays, and oversaw the publication. During the project each person was responsible for their areas of expertise. Jay covered foreign relations, Madison covered the history of republics and confederacies, along with the anatomy of the new government and Hamilton covered the branches of government most pertinent to him: the executive and judicial branches, with some aspects of the Senate, as well as covering military matters and taxation. The papers first appeared in "The Independent Journal" on October 27, 1787.