Stephen Bullivant is Professor of Theology and the Sociology of Religion, and Director of the Benedict XVI Centre for Religion and Society. He holds doctorates in Theology (Oxford, 2009) and Sociology (Warwick, 2019). He joined St Mary's in 2009, having previously held posts at Heythrop College, London, and Wolfson College, Oxford. Professor Bullivant has also held Visiting fellowship at the Institute for Social Change (University of Manchester), Blackfriars Hall (University of Oxford), and the Institute for Advanced Studies (University College London). Professor Bullivant has published ten books, including: Mass Exodus: Catholic Disaffiliation in Britain and America since Vatican II (OUP, 2019), Why Catholics Leave, What They Miss, and How They Might Return (2019; with C. Knowles, H. Vaughan-Spruce, and B. Durcan), The Oxford Dictionary of Atheism (OUP, 2016; with L. Lee), and The Trinity: How Not to Be a Heretic (2015).