This chapter provides a theoretical framework for the book’s central argument that the concept of gravity should be reconceived as a function of values and goals to promote the legitimacy of international criminal law. It does so by: (1) explaining how the book uses the concept of legitimacy; (2) describing the pervasive goal-independent approach to gravity as a justification for regime decisions, and explaining the proposed reconceptualization; (3) elaborating a theory of international criminal law as both a tool, and constructor, of the global justice community; and (4) suggesting some of the global values and goals that ought to guide regime decisions.