This collection consists mostly of correspondence from William B. Preston to his wife Harriet during the period 1857-1900. There are a few letters from Harriet to William, and a couple from William to their children, Allie and Willie. Two letters from William Preston, Jr. in 1889 to his parents and sister describe his LDS mission in Europe. There is also a letter from R. L. Preston, William's nephew, detailing his research into the Preston family genealogy, and a letter from Joseph F. Smith consoling the Prestons after the death of two of their children. Additionally, several letters from William's daughter, Mary, who served as a nurse in Europe during World War I, are also included. The letters are arranged chronologically and separated into folders. The locations listed on the inventory after the name of the writer indicate where the letters were sent from.

In addition to correspondence, this collection contains several other items: two mission diaries kept by William while he served in Liverpool, England (1867-1868), a certificate proclaiming William Mayor of Logan, a certificate from when William Preston became a member of the Utah House of Representatives, and a Resolution by the Brigham Young College in Logan in memory of William Preston following his death in 1908. The mayoral certificate and Resolution are in containers separate from the boxes.

Seven folders in Box 2 contain miscellaneous papers from the Bullion, Beck, and Champion Mining Company of Salt Lake City, where William Preston served as treasurer. The papers do not directly mention William, however.