The Dewey papers consist of 545 items relating to the Dewey family including 436 letters, 46 financial records, 9 accounts, 12 school exercises, 17 medical books, and 20 miscellaneous items. The bulk of the collection is comprised of letters written to Dwight by his brother Duane; his business partner, E.B. Holden; his uncle, Anson Hart, a banker and realtor in Iowa City; his Keokuk pastor, Reverend John H. Day; and many nieces and cousins. Only a few letters were written by Dwight Dewey. Though almost no mention is made of the Civil War, the letters help to provide insight into civilian life during the war. The letters concern business and family life and track his movements from Iowa to Washington, and to New York.
A substantial number of items relate to the Dewey family's business dealings. The Financial Records series contains receipts for property transactions, commissions and services, real estate taxes, and ledgers from the family store. The Accounts series holds R. Dwight Dewey's physician account books from 1806-1820, 1815-1842, and for 1838; and Dwight C. Dewey's account books for 1848-1851. These books document a doctor's business practices in the first half of the 19th century.
The School Exercises series consists of Dwight Dewey's student essays and penmanship exercises. The Medical Notes series contains detailed notes from some his coursework in medical school. The Medical Books and Journals are notebooks kept by Royal Dwight Dewey while practicing medicine in Turin, New York. He made notes on treatments for colds, syphilis, colic, epilepsy, burns, dysentery, and other ailments, and listed medicinal recipes such as "Pectoral Syrup," "Rheumatic Liniment," and others. There are no accounts of Dwight's medical practice.
Miscellaneous items include wedding invitations; printed materials for the Keokuk Female Seminary, the state University of Iowa, and the Iowa Medical Society; and two lists of medical instruments, one with drawings of scalpel types.