J. Willard and Alice Sheets Marriott formed a business partnership in 1927 that produced one of the twentieth century's most successful hotel and restaurant chains. Not only did they make a lasting impact in the service and hospitality industry, but they left their mark in the political, religious, and academic arenas as well. Their papers range in date from the 1920s to the 1980s and have been divided into nine sections.

The Marriott Library Exhibits Committee records (1968-1982) document the various exhibits held at the Marriott Library. When the library first opened in 1968, a committee was formed and their displays were shown in the library atrium.

The Frederic Rowland Marvin letter (1915) is from Frederic Marvin to John Thomas Lee concerning an article Lee wrote about Abigail Adams.

The Brad Mauss papers (2000-2001) contain correspondence, notes, booklets, planning maps and drawings regarding the logistics of the 2002 Winter Olympics held in Salt Lake City, Utah.

The G. Stanley McAllister papers (1920-2006) contains copies of typed and handwritten diaries, letters, and biographical information, most of which were written by McAllister during the time he served in the Eastern States mission for The Church of Jesus Christ of Latter-day Saints (LDS Church). McAllister was a New York City merchandising executive.

The John McAllister correspondence (1892-1926) was written by his children and other family members from St. George, Cedar City, Salt Lake City, Provo, Manti, Goshen, and Winter Quarters, Utah. The authors of the letters include Minerva W. McAllister, Dan McAllister, Emma G. Brown, Emily McConnell, and Brigham McAllister. There are also a number of letters from Brigham McAllister to Isabell Tuttle.

The Wilson McCarthy papers (1917-1957) contain personal and business materials concerning McCarthy (1884-1956), a prominent business man in Salt Lake City and Denver. Wilson McCarthy began his career in Utah as an attorney, judge, and state senator. He also served as a regent of the University of Utah and the western director of the Reconstruction Finance Corporation. He is primarily known as an officer in various railroads, particularly the Denver and Rio Grande Western.

The John Jasper McClellan correspondence (1917 and 1919) consist of three letters from McClellan (1874-1925) to his daughter, Geneve.

The Daniel McCool papers (1888-2008) contain correspondence, research files, published and unpublished articles, news clippings, legal documents, government publications, pamphlets, brochures, and interview transcripts. Daniel McCool has taught at the University of Arizona, Texas A&M University, and the University of Utah. Formerly the Director of the American West Center at the University of Utah, McCool is currently the Director of Environmental Studies.

The Scott D. McCoy papers (2002-2010) contain correspondence, research and notes relating to Scott McCoy's tenure in the Utah State Senate (2005-2009). Also included are materials related to the Don't Amend Alliance (2003) and Equality Utah.

The G. Vernon McCracken papers (1943-1945) consist of a collection of correspondence and memorabilia from his service in the 84th Naval Construction Battalion during World War II.

The William Clark McFerrin papers (1906) contain correspondence written to McFerrin (1848-1916) regarding the San Francisco earthquake of 1906.

The Sheridan L. McGarry papers (1864-1950) contains an article, correspondence, notes, and news clippings relating to the study of LDS currency. McGarry researched and wrote a lengthy article on the subject, which was published in The Numismatist.

The Ralph Martin McGrath term paper (1965) is titled "Was Austin Cowles a Conspirator against the Life of the Prophet?" The paper conclusively demonstrates that Austin Cowles, of whom McGrath is a decendant, had no role in the conspiracy against the LDS prophet, Joseph Smith.

The Llewelyn Riggs McKay papers (1911-1960) contain correspondence, newspaper clippings, reports and articles. Of special note is a bound volume consisting of a typescript of McKay's missionary journal and correspondence, complied and edited by his children, Douglas R. McKay and Bonnie M. Nelson. This collection also includes many original letters between the McKay family throughout McKay's schooling, teaching and army service.

The David McKenzie papers (1860-1962) include early programs, playbills, tickets, scripts, librettos, and other materials related to the Salt Lake Theater, as well as some personal papers of David McKenzie (1833-1912), manager of the theater.