The role of libraries with regard to post-literate people is to provide suitable follow up reading material for these people so that they do not relapse into illiteracy. A public library service plays an indispensable part in any progressive educational system. It is particularly essential for the success of any literacy campaign and the adult education program in general. The part the Tanganyika Library Service plays in post-literacy education is the subject of this paper. The Tanganyika Library Service has been given the responsibility of promoting, establishing, equipping, managing, maintaining and developing libraries in mainland Tanzania. Emphasis of the current Five Year Development Plan (1969-1974) is on the extension of services to rural areas. The Tanganyika Library Service promotes the publication of books by guaranteeing a market for new books through the purchase of multiple copies which are distributed to all service points in the country. The role of the library in post-literate programs is especially important in countries with a small per capita income for it is the only source of free reading material. (Author/NH)