Isadore Gilbert Mudge was born on March 14, 1875 in Brooklyn, New York. She attended Brooklyn's Adelphi Academy and received a bachelor of philosophy degree from Cornell University, where she was elected to Phi Beta Kappa for her outstanding scholarship. Following her graduation from Cornell, Mudge went to Albany to attend the New York State Library School, receiving her Bachelor of Library Science degree with distinction in 1900. Mudge first worked as head reference librarian at the University of Illinois: Urbana in 1900, and was also an associate professor at the University of Illinois Library School. In 1903, she accepted the position of head librarian at Bryn Mawr, where she worked until 1908. From 1910 to 1912, Mudge also served as a part-time instructor in reference and documents at Simmons College. In 1911, Mudge began working in the library at Columbia University, which allowed her the opportunity to further her goal of increasing student independence in research and improving reference collections with several specific types of sources, including a dictionary, an encyclopedia, and an atlas, among others. She coined the phrase “material, mind, and method” to describe her reference philosophy when she began teaching the class “Bibliography and Bibliographic Methods” as an associate professor at Columbia's School of Library Services in 1927. Between 1917 and 1936 while at Columbia, Mudge edited the American Library Association's Guide to Reference Books, a comprehensive bibliography of reference tools. She retired in 1941 and died on May 16, 1957 in Lutherville, Maryland. To honor her career, the ALA created the Isadore Gilbert Mudge Citation in 1958 for librarians who make distinguished contributions to reference librarianship.

This collection contains materials created by and about Isadore Gilbert Mudge, a reference librarian at Columbia University from 1911 to 1941. The collection consists of correspondence, notes, publications, and a copy of a dissertation about Mudge written by John Waddell. The material within all folders, where applicable, is arranged in chronological order. The collection contains significant material in the form of card files (arranged alphabetically) and other printed materials (including correspondence) relating to Mudge's notes on children's periodicals that were used by Columbia's Library Cataloging Department to prepare cards for the Historical Collection of Children's Literature. John Waddell's manuscript The Career of Isadore G. Mudge is arranged in two folders by chapter (folder 1 contains chapters 1-7; folder 2 contains chapters 8-13 and appendices). The other correspondence in this collection ranges from professional to personal with family members and other friends, dating from 1910, approximately the time of her appointment at Columbia, to her death in 1957. The last series in the collection of writing and other printed materials includes Mudge's publications in Bulletin of the ALA (1930), The Library Journal (1934), New York State Education (1949), The Saturday Review (1952), and The Bulletin of the NYPL (1953), as well as her reference guides (1911-1934), speeches and articles (1934-1942), and her travel journal (1939). This series also contains various other personal materials, including biographical and family information, legal and financial documents, and passports.