Friends of the Constitution: Writings of the "Other" Federalists, 1787-1788, eds. Colleen A. Sheehan and Gary L. McDowell
The Documentary History of the Ratification of the Constitution (volumes VIII-X, on Virginia, are especially interesting)
Federalism: The Founders' Design by Raoul Berger
The Politically Incorrect Guide to the Constitution by Kevin R.C. Gutzman
Who Killed the Constitution? The Fate of American Liberty from World War I to George W. Bush by Thomas E. Woods, Jr. and Kevin R.C. Gutzman
The Constitutional Thought of Thomas Jefferson by David N. Mayer
Reclaiming the American Revolution: The Kentucky and Virginia Resolutions and Their Legacy by William J. Watkins, Jr.
33 Questions About American History You're Not Supposed to Ask by Thomas E. Woods, Jr.
New Views of the Constitution of the United States (1823) by John Taylor (probably the best Jeffersonian overview of the Constitution; available in html and at Google Books)
A Brief Enquiry into the True Nature and Character of Our Federal Government (1840) by Abel Upshur. A brilliant and unjustly neglected short book on the nature of the Union created by the Constitution. Available online and as Classic Reprint No. 120 from Vance Publications.
"The Original Meaning of the Commerce Clause" by Randy Barnett
Virginia's American Revolution: From Dominion to Republic, 1776-1840 by Kevin R.C. Gutzman
"Madison and the Compound Republic" by Kevin Gutzman (later published as "'Oh, What a Tangled Web We Weave": James Madison and the Compound Republic," Continuity 22 : 19-29)
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