Andrew Louth is Emeritus Professor of Patristic and Byzantine Studies in the Department of Theology and Religion at Durham University. He is the editor of the journal Sobornost, and editor, with Professor Gillian Clark, of the series Oxford Early Christian Studies and Oxford Early Christian Texts. Lewis Ayres is Professor of Catholic & Historical Theology in the Department of Theology and Religion at Durham University. John Behr is Regius Professor of Humanity at the University of Aberdeen.