For one thing ,each book covers a different time period "Creation"covers 1776-1787,and "Empire" covers 1787-1815.Also "Empire of Liberty" is apart of the Oxford History of America series where Dr. Wood was selected to write on this period of time. "Creation of the American Republican" was a subject Wood chose himself.Personally I believe "Creation" is one of the best books written about this time , and I would definitely recommend to read first.