The Interstate Commerce Commission (ICC) (defendant) issued an order affecting interexchange traffic rates among railway carriers. The order was based in part on the carriers’ annual reports, which they filed with the ICC. The ICC trial examiner stated during the proceeding that he would refer to the carriers’ annual reports, but did not introduce the annual reports into evidence. The reports were filed with the ICC by statute, and in relying on the reports, the trial examiner relied on an ICC rule that the ICC would generally take notice of such reports. A group of railway carriers (plaintiffs) brought suit challenging the ICC’s order. The district court enjoined enforcement of the order, and the government appealed directly to the United States Supreme Court.