These three books, all relatively short and available online or for purchase, are an excellent starting point on sound economics.
An Introduction to Austrian Economics by Thomas C. Taylor; online here and here (.pdf)
The Declaration of Independence
The U.S. Constitution
The Articles of Confederation
The Federalist Papers and the Anti-Federalist Papers
Virginia Resolution of 1798
The Kentucky Resolutions of 1798
The Kentucky Resolution of 1799
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 Constitution: Four Disputed Clauses" (mp3 audio) by Thomas E. Woods, Jr. (the Woods audio archive contains several dozen lectures, some of which involve the Constitution)