Constitutional originalism stakes law to history. The theory's core tenet--that the United States Constitution should be interpreted according to its original meaning--has us decide questions of modern constitutional law by consulting the distant constitutional past. Yet originalist engagement with history is often deeply problematic. And now that a majority of justices on the United States Supreme Court champion originalism, the task of scrutinizing originalists' use and abuse of history has never been more urgent. In this comprehensive and novel critique of originalism, Jonathan Gienapp targets originalists' unspoken assumptions about the Constitution and its history. Originalists are committed to recovering the Constitution laid down at the American Founding, yet they often assume that the Constitution is fundamentally modern. Rather than recovering the original Constitution, they project their own understandings onto it, assuming that eighteenth-century constitutional thinking was no different than their own. They take for granted what it meant to write a constitution down, what law was, how it worked, and where it came from, and how a constitution's meaning was fixed. In the process, they erase the Constitution that eighteenth-century Americans in fact created. By understanding how originalism fails, we can better understand the Constitution that we have.