Lafayette: Prisoner of State is the first book-length study of the five-year captivity of Marie-Joseph Paul Yves Roch Gilbert du Motier, Marquis de Lafayette, by a coalition of Austrian and Prussian forces during the French Revolution, including international efforts to win his release. Paul S. Spalding constructs this original history of Lafayette's imprisonment by drawing in part on extensive manuscript collections in America and Europe, some of which have only recently been made available to researchers.

The "hero of two worlds," Lafayette is widely known as the French marquis who fought alongside the colonials in the American Revolution and then played a leading role in the early stages of the French Revolution. He is much less remembered for having spent five years as a political prisoner, but his incarceration was a matter of great notoriety at the time. In August 1792 radical Jacobins overturned the young French constitution and began massacring opponents. While fleeing for his life, Lafayette fell into the hands of Austrian and Prussian troops intent on invading France and restoring the monarchy. A special tribunal decided that Lafayette was too dangerous to release and declared him a prisoner of state. Thereafter he was moved through a series of prisons in western and central Europe from 1792 to 1797. During this time Lafayette's supporters on both sides of the Atlantic actively campaigned for his release, eventually championing his cause before the British Parliament, the U.S. Congress, France's Directory and Councils, and European peace talks in northern Italy. Lafayette's imprisonment became a cause of international debate, moving France to demand his release as a condition of European peace.

Using firsthand accounts, police and military records, and private correspondence, Spalding delineates both public and covert efforts to gain Lafayette's release by negotiation or force, including the prominent role of South Carolinians Thomas Pinckney, for a time the dean of America's ambassadors, and Francis Kinloch Huger, a medical student turned secret agent. Spalding's research also provides a case study in how dedicated men and women, most without political office, can frustrate state-sponsored efforts to suppress dissent and dissenters.