The Trevor Southey papers (1917-2015) contains both his personal and professional records. These materials document Southey's career as a Utah artist and a gay activist.

The Sowards-Tibbals family papers (1913-1915) consist of copies of a letter and postcards. The letter recounts the memories of Elisabeth C. McCanne and her family's move from North Carolina to Missouri. She wrote the brief history on February 16, 1913, her 88th birthday, in Denver, Colorado.

The Lonnie Sparks papers (1990-1991) consist of correspondence and an article regarding the interpretation of the Pearl of Great Price. A few other items are also included with the collection.

The John D. Spencer papers (1895-1933) contain correspondence, speeches, biographical sketches, programs, and material related to Spencer's affiliation with the Salt Lake Arts Center, the Fine Arts and Letters Society of Utah, the Salt Lake City Opera Company, and other organizations. John D. Spencer (1858-1947) was an insurance executive and patron of the arts.

The Orson Spencer letter (1852) is from Spencer to his son-in-law, Hiram B. Clawson and concerns the estate of Samuel A. Curtis, the father-in-law of Orson Spencer, and how that estate might affect Spencer's children.

The Hillary W. St. Clair papers (1896-1997) contain some of St. Clair's published research, calculations, notes and workbooks during his time with the Bureau of Mines, and other research in the field of metals and mining. Materials of particular interest include St. Clair's notes and lecture material regarding the history of American mining. This was later published by the Bureau of Mines in a book called Mineral Industry in Early America.

The Theodore H. Stanley papers (1960s-2000) consist of the collected works and papers of esteemed anesthesiologist Theodore H. Stanley, one of the team members who worked on the first total artificial heart replacement developed at the University of Utah. The collection includes research, published articles, correspondence, and models/diagrams of Dr. Stanley's work.

The James T. Steel correspondence (1880-1971) consist of a letter from Steel to his brother-in-law in South Africa in which he describes his family and contemporary issues in Utah. The collection also includes a letter from the U.S. Consulate General in South Africa and two letters concerning the provenance of the collection.

The Frank Everett Steele correspondence (1943-1944) is mostly to and from his parents and his brother Roger, while he was serving in the U.S. military during World War II.

This collection consits of a handwritten and signed letter (1892) from M. M. Steele (Mahonri Moriancumer) to his father, John Steele, regarding a mutual acquaintance's infidelity and the purchase of livestock.

The Lynn Stegner papers (1977-1997) consist primarily of her manuscript drafts, some with critiques, notes, and research materials. It also contains correspondence.

The Page Stegner papers (1969-2001) consist of manuscript drafts, finished manuscripts, galleys, published essays, interviews, correspondence, and news articles. This collection also contains drafts through page proofs of Marking the Sparrow's Fall: Wallace Stegner's American West, with an introduction written by Page Stegner.

The Omer Call Stewart papers (1925-1989) consist mainly of personal items and published articles. Correspondence, news clippings, diaries, book reviews, articles, and student papers are included. Omer Call Stewart (1908-1991) was an an anthropologist from Utah who spent most of his professional career at the University of Colorado.

The James D. Still Mormon history collection (1834-2010) contains articles, clippings, correspondence, an index, and other research materials on Mormon history, particularly Oliver Cowdery, the writing of the Book of Mormon and the Book of Abraham, and the relationship between Masonry and the LDS Church.

The Thomas G. Stockham papers (1951-1994) provide information about the personal and professional life of Thomas Greenway Stockham, Jr. (b. 1933). The papers include personal documents, correspondence, teaching and business records, scientific and technical reports and manuals, project notes, and published and unpublished documents. Stockham is best known for his development of digital sound, his contributions to computer image processing procedures, and his work on the Watergate tapes.