The 5,000 Year Leap
Cleon Skousen
A good place to start. Explains the 28 principles of freedom a nation must practice to remain free.
The Making of America
W. Cleon Skousen
This 800 plus page book expounds on the principles and ideas of the founding fathers in designing our form of government. Direct quotes from the founders explains their thinking and reasoning as they debated and deliberated our constitution.
A Guide for Learning and Teaching The Declaration of Independence and The U.S. Constitution
Joseph Andrews
For the serious student, this book uses original sources documents and applies the classical learning methods of the Founders.
The Law
Frederic Bastiat
Original Intent
David Barton
Betrayed by the Bench
John Stormer

Plymouth Rock Foundation
www.plymrock.org
Offers two excellent CD study courses on the Constitution