The Library first began to offer services in support of the Department of University Extension in 1935, loaning books to persons enrolled in extension courses. It was initially the responsibility of the Reference Division, and later the Circulation Division, and did not become an administratively separate division until the 1940s. In 1949 the Extension Library also began mailing books to students enrolled in correspondence courses. In 1952 it became strictly a mailing library for students outside the Vancouver and Victoria areas, serving credit-course students, drama groups, and the general public. By 1965 the public library system around British Columbia had evolved enough to allow the book-mailing service to be discontinued. Still, drama groups and correspondence students - and services for the drama groups also were soon phased out. Since then, the Extension Library has continued to provide reading materials for the University's extra-sessional and distance education students.
The sous-fonds consists of records created by the Extension Library in the course of its activities and includes correspondence, reports, and statistical data. It is arranged in two series: General Files and "In-Service Books," the latter dealing with books required for distance education courses.