I was born in London but raised in Zimbabwe, completing my higher education and first theological appointments in South Africa. I was a minister, principal of Tshwane Theological College near Pretoria and part-time researcher at the University of South Africa before joining Selly Oak Colleges as Director of the Centre for New Religious Movements in 1995, becoming an honorary lecturer and, from 1999, a lecturer at the University of Birmingham. I was awarded a Chair in 2005. I retired in December 2019, when I was also given the Emeritus title.
My main interests are in the areas of the history, mission and theology of Pentecostalism in Africa and Asia. I am the author of five books on South African Pentecostalism, one on African independent churches, and three books on global Pentecostalism that have received international acclaim. My Introduction to Pentecostalism has been translated and published in Spanish, Portuguese, Swedish and Korean, and now has a second edition.
I am also the author of many articles, and have joint-edited five collections on Pentecostalism. I was editor of the peer-reviewed journal published at Equinox, PentecoStudies. I am a founder-member of the European Research Network on Global Pentecostalism which conducts research in European universities, and I also serve on the international editorial board of five academic journals. I am an internationally well-known scholar in my field.