In this Introductory chapter to “Amending America’s Unwritten Constitution,” the editors invite readers to consider the puzzle presented in the book: How to amend America’s unwritten constitution? The editors undertake a systemic inquiry into each of the major themes raised by the puzzle: What is a “constitution,” what is “America’s” constitution, what does it mean to “amend” a constitution, and how might we identify an amendment to an “unwritten” constitution, specifically the unwritten constitution of the United States. As the editors set out to answer these questions, they survey the existing literature in the field to lay the foundation for the chapters to follow. They introduce the chapters as well as how each of them illuminates the answer to the major thematic questions raised and explored in the book. What results is ultimately both a proper introduction to this book and also an important scholarly resource to understand constitutional change in the United States.