Mark O'Brien OP is a member of the Australian Province of the Dominican Order, also known as the Order of Preachers (OP). He entered the Order in 1967 and studied theology in Dominican houses of study in Canberra and Dublin. He was ordained to the priesthood in 1973 and completed post-graduate studies at the Pontifical Biblical Institute, Rome, in 1976. He taught Old Testament studies at Yarra Theological Union, Melbourne, from 1977 and completed a doctorate in Theology at the Melbourne College of Divinity in 1987, now the MCD University of Divinity. He is the author of The Deuteronomic History Hypothesis: A Reassessment and has co-authored several books on the Old Testament with Antony F Campbell SJ. He is currently Dean of Studies for his Province and lectures in Old Testament studies at Catholic Theological College and Yarra Theological Union, both colleges of the MCD University of Divinity.