Administrative law provides the concepts and the logical framework that explain American government. The fundamental questions of modern American government and of administrative law are the same: by what right do the agencies of government operate? Are there limits on their powers? Who sets the limits? What are the limits? Where is the line drawn between Congress and the agencies in the allocation of policy–making authority? How much access to the courts should be available to the citizen who seeks protection of his or her individual rights against government — agency — power? To what extent must the government spell out rules in advance, and to what extent may a citizen find himself or herself in trouble for doing something that had not previously or usually resulted in prosecution?