The Jahn Library comprises a unique collection of literary works in over ninety languages, including the former colonial languages, several world languages and numerous African languages. Some of the collected books are also interesting as objects, e.g. as first editions of important works or as book copies with handwritten dedications by authors, but also in terms of what their design reveals about the respective publication context. The Jahn Library is one of the Johannes Gutenberg University Collections.

The Jahn Library originated as the private collection of Janheinz Jahn (1918-1973), whose interest in African literature was awakened in 1951 during a lecture by the Senegalese poet and statesman Léopold Sédar Senghor in Frankfurt/Main. Through his work as a translator, publisher, bibliographer, author and freelance journalist, Jahn contributed significantly to the public perception of African literature in Germany, but also worldwide. The Jahn Library is used by students and researchers at the JGU Mainz as well as by international visiting scholars; and it is also available to the wider public.

In addition to the seminar courses on African literature regularly offered at the department, the Jahn Library organises international Janheinz Jahn symposia, readings with writers from Africa, as well as other events (such as exhibitions, workshops, lectures, library tours) at irregular intervals.