This Special Issue of JSAS explores the little-recognised, shifting importance of grassroots ecumenism in religious experience and public life. 1 The cases that we present come from across southern Africa, from Rwanda to Angola, to Zambia and Botswana, to South Africa and Swaziland. We match this breadth with arguments that also draw widely, for an emerging area of interest in popular religious change, with contributions from anthropology, social history, theology and religious studies. Among the ecumenical changes we discuss are, perhaps most surprisingly, ones in which counterpublics 2 are anti-establishment, transgressive, even disruptive, as they bring strangers together, with religious motives and moral passion, 3 and oppose dominant publics in the making of public cultures. In our cases, the ecumenical and the agonistic transform together. Most of the believers are Christians who contend, among themselves, with endemic differences and divisiveness, with entanglement in ethnic or identity politics, with dialogue that appeals for reconciliation but that risks an argumentative, not assuaging, encounter. Anti-establishment critique, condemning the theology and practice of entrenched churches, often thrives alongside or even motivates appeals for new, more inclusive unity, even extending between Christianity and other faiths, an extension labelled 'inter-religious'. Some Christians who seek unity and fellowship do so more or less uneasily in the presence of schism and competition, occasionally to the exclusion of those castigated as not 'real Christians'. Given their religious diversity, others take turns, sharing more or less wholeheartedly in common ritual, such as at funerals, where everyone agrees on a spiritual vision of the good death, with consolation for the bereaved. Still others find themselves in conflict over how and even whether Christians should cross over and enter into any religious co-habitation with non-Christians, for example by participating in animal sacrifice and other traditional ritual or by celebrations and rituals with Jews or Muslims and others. 4 We focus our accounts of variable transformations in grassroots ecumenism on a series of interrelated questions. How far and in what ways is grassroots ecumenism ordinarily homegrown, spontaneous or emergent according to conflict or competition in distinctively local circumstances? Does it change radically or in response to the growth of other social and cultural movements, such as the anti-apartheid movement or nationalism, and, if so, how? When