The Comprehensive Bibliography of Chadic and Hausa Linguistics, 4th edition, includes works written on Chadic and Hausa languages and linguistics dating from 1790 to the present. The bibliography contains published books and articles as well as unpublished Ph.D. dissertations and master’s theses. The bibliography is international in scope and covers works regardless of the language in which they were written. For example, there are approximately 500 entries written in French, 300 in German, 125 in Hausa, and 100 in Russian. Titles of works in languages other than English, French, or German are accompanied by English translations. Russian titles in Cyrillic script are transliterated into Roman script. Book reviews are listed under the entry for the book being reviewed. In addition, there is Book Review Author Index that indicates all the books that any individual has reviewed. Finally, the bibliography contains a small section consisting of obituaries, (auto-)biographical essays, and related works on major scholars, now deceased, who have contributed significantly to Chadic and Hausa linguistics. The first edition of this online bibliography was published in 2012 at Bayreuth University. The second edition (2013) and the third edition (2015) were published at Indiana University (http://hdl.handle.net/2022/16600). This is an open access work fully and freely available for education, research, and other scholarly purposes.