Andrew Finlay Walls, OBE (1928–2021), Honorary Professor of World Christianity, was a pioneering historian of Christian missions and their reception, and in many ways the architect of the field of study now known as world Christianity. Trained as a patristic scholar at the University of Oxford, he went to Sierra Leone in 1957 to teach at Fourah Bay College. There and at the new University of Nsukka in Nigeria (1962–66) he studied the growing churches of Africa and their history.

At the University of Aberdeen where he taught between 1966 and 1986, he became a scholar of international renown, establishing the Centre for the Study of Christianity in the Non-Western World (now known as the Centre for the Study of World Christianity), and supervising many research students who became leaders in both church and academy. The Centre was established as a library and archival resource, documenting the history of missions and the growth of non-western Christianity: the students followed, attracted by the sources.