Some constitutional amendments are not amendments at all. They are self-conscious efforts to repudiate the essential characteristics of the constitution and to destroy its foundations. They dismantle the basic structure of the constitution while at the same time building a new foundation rooted in principles contrary to the old. Changes on this scale are not properly called constitutional amendments. They are better understood as constitutional dismemberments. A constitutional dismemberment is incompatible with the existing framework of the constitution. It intends deliberately to disassemble one or more of the constitution’s elemental parts by altering a fundamental right, an important structural design, or a core aspect of the identity of the constitution. To use a rough shorthand, the purpose and effect of a constitutional dismemberment are the same: to unmake the constitution. But what, then, is a constitutional amendment? This chapter explains that there are four fundamental features to a constitutional amendment: its subject, authority, scope, and purpose. The most important feature of an amendment is its scope, which at all times must not exceed the boundaries of the existing constitution. This chapter therefore defines a constitutional amendment in terms of what it is and what it is not, with illustrations drawn from around the globe. This chapter considers constitutions from Barbados, Belize, Brazil, Canada, Dominica, Guyana, Ireland, Italy, Jamaica, Japan, New Zealand, and the United States.