The term ‘popular Islam’ at once suggests denial or fragmentation within the Great Tradition or ‘orthodoxy’ in Islam as well as a degree of hostility on the part of those Islamicists and Muslims whose understanding of the oneness of God extends to the indivisibility of His Community. Social scientists may be expected to embrace the notion with more enthusiasm, being accustomed to observing Islam ‘from below’, but legitimate disquiet follows after plumbing the analytical shallows implicit in simple attributions of ‘popular-ness’ to matters of causation, motivation or ideology. Yet, with that said, few students of Islam in Africa cannot cite examples of belief or practice that represent ‘popular Islam’, and most would agree that this frequently bears some relation to the dramatic expansion of Islam during this century in Africa. These were some of the considerations that lay behind the selection of the theme ‘Popular Islam in Twentieth- Century Africa’ for a two-day symposium held at the University of Illinois in April 1984. Five of the papers presented at that meeting – by Louis Brenner and Murray Last, Mbye Cham, Lidwien Kapteijns, Paul Lubeck and Gabriel Warburg – are published with an essay by Abdullahi Osman El-Tom in this issue.