Libertarian Philosophy
* Second Treatise of Government by John Locke
* Libertarianism in One Lesson by David Bergland
* Libertarianism: A Primer by David Boaz

Noninteventionistic Policy
* A Foreign Policy for Americans by Robert A. Taft
* “War” in Stanford Encyclopedia of Philosophy

Constitutional Law
* View of the Constitution of the United States by St. George Tucker

Secret Combinations
* Perfectibilists by Terry Melanson
* The Doctrine of Fascism by Benito Mussolini
* The Hidden Things of Darkness by Christopher S. Bentley

Historical Events
* A Choice, Not an Echo by Phyllis Schlafly

I don’t think that an understanding of the U.S. Constitution is complete without also understanding the “just and holy principles” that inspired it, such as those expounded in the U.S. Declaration of Independence. This requires an understanding of libertarian philosophy, for which I’ve listed three of the best books that I’ve ever read about this subject. As for foreign policy, I haven’t read Taft’s book yet but include it tentatively—and I found this encyclopedia article about war exceptionally useful. Although I love Skousen’s The Making of America, I found St. George Tucker’s commentary at least as valuable in understanding the Constitution’s various passages, as did many other early-19th-century Americans. I find Terry Melanson’s book about the Illuminati on par with those of Robison and Barruel, and it includes valuable additional information that has come to light since they wrote theirs. I think that it’s important to study fascism as a significant noteworthy variant of communism, and would rate Mussolini’s Doctrine of Fascism to be of nearly equal importance with Marx’ Communist Manifesto. Bentley’s book is the best that I’ve read yet to analyze what the scriptures teach about secret combinations. And Phyllis Schlafly’s book explains how socialists have been manipulating the Republican Party, which is especially important for those who want to take political action to overcome their political naivete and understand what tactics they can expect from their collectivistic opponents.

1. Notes of Debates in the Federal Convention of 1787, by James Madison.
2. Commentaries on the Laws of England, by Sir William Blackstone.
3. View of the Constitution of the United States with selected writings, by St. George Tucker.

These books are Way, Way, Way more important for understanding the constitution than, say, The Federalist Papers, because while The Federalist Papers are very valueable, they were a special plea for ratification; then you have St. George Tuckers work which is the only full in-depth view of the constitution by a founding father!
There is Blackstone, which is how many founding fathers learned law. Blackstone reveals much of the basis for constitutional law; plus English common law: the meat of much U.S. law. Blackstone should be read with St. George Tucker by the way.
Then you have Notes of Debates in the Federal Convention of 1787. James Madison, during the constitutional convention, took notes of what happened, what people said, and most of what we know about the constitutional convention ultimately comes from this book.
May I now suggest a few less important additions to your list?

4. The Lincoln-Douglas Debates.
5. Robert’s Rules of Order (Classic Edition), by Henry M. Robert.
6. A Manual of Parliamentary Practice, by Thomas Jefferson.

Bliss Tew compiled a similar list. Here is Bliss Tew’s list:

The Constitution — The Founding Fathers

The Declaration of Independence — 56 Founding Fathers

The Federalist Papers, Hamilton, Madison, Jay (1961 Edition, 606 pages,pb)

The Anti-Federalist Papers, edited by Ketcham.

The Lives of The Signers of the Declaration of Independence, by
Lossing (1995, ed. 384 pages)

And not a shot is fired, by Jan Kozak (1999 Edition. How communist
took over Czechoslovakia from within.)

The Communist Manifesto, by Karl Marx (1848 original. 1997 Edition, 60
pages in my library)

Final Report On The Bombing Of the Alfred P. Murrah Federal Building,
April 19, 1995, by the Oklahoma Bombing Investigation Committee (2001)

Architects of Conspiracy, by William P. Hoar (1984)

Inside the United Nations– A Critical Look at the UN, by Dr. Steve Bonta

The French Revolution, by Nesta H. Webster(1919)

Reflections on the Revolution in France, Edmund Burke (1790 original.
1955 edition Liberal Arts Press, Inc.)

Fire in the Minds of Men, by Billington (the Librairan of the Library
of Congress)

The Illusion of Victory, by Thomas Flemming

Betrayed, by Dr. Joseph D.Douglass,Jr. (2002)

Red Cocaine: The Drugging of America and the West, by Dr. Joseph D. Douglas, Jr.

Day of Deceit, by Robert Stinnett (Touchstone publishing, 2000)

Foundations– Their Power and Influence, by Rene A. Wormser (Covenant
House Books, 1958)

The Black Book of Communism — Crimes , Terror, Repression, by
Stephane Courtois, Nicolas Werth, Jean-Louis Panne, Andrezej
Paczkowski, Karel Bartosek, and Jean-Louis Margolin. Translated by
Jonathan Murphy and Mark Kramer. (First published in French. The
English edition: Harvard University Press, 1999)

Reds In America , by R. M. Whitney, first published in 1924. (1970
edition, Western Islands Publishing)

The Venona Secrets — Exposing Soviet Espionage and America’s
Traitors, by Herbert Romerstein and Eric Breindel. (Regnery 2000)

Global Tyranny …Step by Step, The United Nations and the Emerging
New World Order, by William F. Jasper (Western Islands 1992)

The United Nations Exposed– The Internationalist Conspiracy to Rule
the World, by William F. Jasper (The John Birch Society, 2001)

Secrets Records Revealed, by Dennis Laurence Cuddy, Ph.D. (Hearthstone
Publishing, Ltd., 1994)

Biographical Dictionary OF The Left, Volume I & II, by Francis X. Gannon

Teddy Bare- The Last of the Kennedy Clan, by Zad Rust

The Lincoln Conspiracy, by David Balsiger and Chatles Sellier, Jr.
(Schick Sunn Classic Books 1977)

The Insiders– Architects of the New World Order, by John F. McManus
(Fifth edition, 2004)

William F. Buckley, Jr.– Pied Piper for the Establishment, by John F.
McManus (2002)

Changing Commands- The Betrayal of America’s Military, by John F. McManus (1995)

Financial Terrorism– Hijacking America Under the Threat of
Bankruptcy, by John F. McManus (1993)

Freedom on the Altar– The UN Crusade Against God & Family, by William
Norman Grigg (1995)

The Prince, Niccolo Machiaveli (Mentor Book, 1952. First published
400-years ago)

America’s Secret Establishment — An Introduction to The Order of
Skull & Bones, Antony C. Sutton (Liberty House Press 1986)

The Rise of The House of Rothschild, by Count Egon Caesar Corti
(Cosmopolitan Books 1928)

J. Reuben Clark– Selected Papers, (5 volumes, BYU Press) compiled by David Yarn

The Year of the Rat– How Bill Clinton Compromised U.S. Security for
Chinese Cash, by Edward Timperlake and William Triplett, II

The Secret Life Of Bill Clinton — The Unreported Stories, by Ambrose
Evans-Pritchard (Regnery 1997)

Philip Dru: Administrator, by Col. Edward Mandel House (1912)

Tragedy & Hope – A History of the World in Our Time, by Dr. Carol
Quigley (Macmillon Co. 1966, 1347 pages)

The Valachi Papers, by Peter Maas (1968)

The Holy Bible

The Book of Mormon

Rick Pearce
Canada