[1] He proceeded to St Catherine's College, Oxford, where he obtained a diploma in Anthropology in 1952 with the aid of a grant from the Nuffield Foundation, and a Bachelor of Letters in 1953.

He studied under Franz Steiner and social anthropologist Sir Edward Evan Evans-Pritchard, who was himself an authority on the Nuer and Azande people of South Sudan, as a graduate student – finishing with a doctorate in 1957.

[1][2] Steiner was working on a multi-language bibliography on the Somali, Afar (Danakil), and Saho peoples, a project for the International African Institute.

[3] He was renowned internationally as the foremost scholar on Somali history and culture, on which he has published numerous articles and books.

[3] His academic interests in Somalia were broad, including published studies in varied fields:[5] Lewis was not appreciated by the Somali President Siyad Barre (1969–1990), so he and his team were prevented from conducting a planned refugee survey in Somalia on behalf of the UNHCR.