Abstract: The traditions of constitutional interpretation in the United States make it possible, and indeed relatively easy, to use interpretation as the vehicle for constitutional adaptation. The distinction between interpretation and alteration is accordingly quite thin. The interpretive traditions are decidedly eclectic. Interpretation relies on the words of the text as understood when they were made part of the constitution, general propositions about how institutional arrangements promote constitutionalism, ideas about the values of democracy and individual autonomy, and much more. This chapter looks at the U.S. constitution, its origins and structure, formation, and basis, as well as the legislature and the executive, the Supreme Court, constitutional amendment, problems and methods of constitutional interpretation, early examples of constitutional interpretation, considerations of administrability, (moderately) disfavoured interpretive methods, presumptive interpretation, preferred interpretive techniques, and eclecticism in practice.