This volume contains sixteen papers on the past and present use of Arabic script to write African languages. These writing traditions, which are sometimes collectively referred to as Ajami, are discussed for single or multiple languages, with examples from all major linguistic phyla of Africa but one (Khoisan), and from all geographic areas of Africa (North, West, Central, East, and South Africa), as well as a paper on the Ajami heritage in the Americas. The papers analyze (ethno-) historical, literary, (socio-) linguistic, and in particular grammatological aspects of these previously understudied writing traditions and exemplify their range and scope, providing new data for the comparative study of writing systems, literacy in Africa, and the history of (Islam in) Africa.