This essay reviews John Dickinson’s neglected classic, Administrative Justice and the Supremacy of Law in the United States. Writing on the cusp of the New Deal, Dickinson helped establish a mainstream, moderate stance about the shape and legitimacy of the administrative state. A closer reading of this work, which is rich in jurisprudential reflection and historical learning, offers a better idea about the structure, promise, and limits of the doctrinal world he helped create.