Jonathan Gienapp, a Stanford historian, challenges the widespread assumption that the Constitution's meaning was fixed at the moment of its ratification in 1788. Through meticulous examination of the debates and practices of the 1790s, Gienapp shows that crucial questions about the Constitution's nature and how it should be interpreted remained unsettled after ratification and were resolved only through subsequent political conflict. The book examines controversies over executive power, the Bill of Rights, constitutional amendment, and judicial review, demonstrating that participants in these debates did not share our assumptions about what kind of document the Constitution was. Some understood it as a written law whose meaning was fixed by its text, while others saw it as a framework that would be completed through practice and precedent. Gienapp traces how the former view gradually prevailed, creating the interpretive assumptions that now seem natural and inevitable. By recovering the contingency of this process, the book challenges originalist claims that the Constitution has a fixed original meaning that can be recovered through historical research. It also complicates progressive assumptions by showing that ideas about constitutional flexibility have their own complex history. Readers will find their taken-for-granted ideas about constitutional interpretation productively destabilized by this careful historical reconstruction.