The Progressive vision of adminsitrative agencies began to be displaced by a pluralist account in which administrative agencies were locations for interest group struggle. The older vision remained strong and guided the Court’s approach to issues such as the standard of review in rate-making cases. The Court also condemned in overstated terms an SEC investigation into probably unlawful speculation by J. Edward Jones, but its decision made only modest inroads in agency procedures. More significant were the Morgan cases, which confirmed the importance to the Supreme Court of the fact that agencies used procedures closely resemeling judicial ones, though the Court allowed some deviations for purely judicial procedures. The chapter concludes with a discussion of the development of the Administrative Procedure, which codified much of what the Court had already done.