Riegel's correspondence in this series is primarily between different awards administrators and judges. Riegel corresponded with approximately 320 different individauls within this subseries. Correspondents of note include Mrs. Dupont, Turner Catledge, and Sol Taishoff.

The two documents in the Radio Conference of Cairo subseries are full text copies of the radio agreements describing acceptable and unlawful use of the radio in attempts to influence populations beyond a nation's borders.

Riegel's public oppinion course focused on the purpose and manner of polling, specifically as a pulse of American Democracy. It elaborated on how to conduct polls and how they influence and show the views of the public. Items in this subseries consist of course syllabi, lecutre notes, and other related materials.

Items in this series pertain to Riegel's personal correspondence between himself and colleagues, friends, and family. Some material is related to or mentions his work, but the majority of the material is about his or other people's personal lives, opinions, and thoughts around world events.