The Sigma Xi, SDSU Chapter 139 Records document the activities and history of the South Dakota State University chapter of Sigma Xi, a scientific research honor society. The collection includes a commemorative booklet marking the first 25 years of the chapter, materials related to distinguished lectures and graduate student research awards, newsletters, documentation of the chapter’s involvement in science and engineering fairs, and a historical paper titled Nicolaus Copernicus: His Life and Work by Marian Wnuk, presented under the auspices of Sigma Xi. These records reflect the chapter’s role in promoting scientific research, recognizing scholarly achievement, and engaging the university and local community in scientific discourse.

This collection is significant for understanding the development and contributions of a major scientific honor society at SDSU. It illustrates the chapter's efforts to foster research excellence, support graduate student work, and organize public-facing events such as lectures and science fairs. The materials serve as a record of faculty and student involvement in the broader scientific community and offer insight into the academic culture of SDSU over several decades.