At the heart of Cass Sunstein and Adrian Vermeule’s insightful and important book, Law and the Leviathan: Redeeming the Administrative State, is a claim that a set of rule-of-law principles underlie and unify disparate doctrines in administrative law. Sunstein and Vermeule offer their interpretive account of administrative law not only to explicate the conceptual foundations of diverse doctrines, but also because they believe this account helps to legitimate the administrative state. The book’s ultimate suggestion is that because administrative law reflects rule-of-law principles in sufficient measure, the administrative actions it governs can be “efficacious as law,” not merely arbitrary commands.