This casebook focuses on five representative agencies to provide students with a more holistic understanding of the structure and functions of agencies, to illustrate the kinds of actions agencies take to implement their statutory mandates, and to provide context for examining the legal constraints on those actions. Two key problems for teaching and learning administrative law are (1) students lack of familiarity with agencies, what they do, and their role in the tri-partite system of government established by the Constitution; and (2) the need to understand new and different agencies and figure out their organic statutes for each new administrative law case. By focusing on five important and representative agencies (the EPA, NLRB, SSA, IRS, and FCC), the book addresses both problems. Extended treatment of these agencies, including one chapter each that uses the agency to present the legal issues surrounding a particular kind of agency action (e.g., EPA to illustrate administrative law issues concerning rulemaking, the NLRB to illustrate the issues arising from agency efforts to make policy through adjudication), provides students with a clearer sense of how agencies are structured, what they do, and how they do it. In addition, our book provides an efficient mechanism for teaching and learning about administrative law: because the principal cases used to illustrate administrative law doctrine and present administrative law issues involve the same five agencies, the need to learn about new agencies and understand new organic statutes is greatly reduced, enabling students and teachers to focus on the administrative law issues in the cases.