John read Human Sciences at Hertford (1972-5) before moving to Cambridge to undertake graduate work in historical demography at the Cambridge Group for the History of Population and Social Structure.
After a year as a demand analyst with the planning division of Shell UK Ltd he joined the Anthropology Department of University College London as a Lecturer in Biological Anthropology. In 1991 he returned to Oxford as a University Lecturer in Historical Demgraphy and Fellow of All Souls College.
From 2005 to 2011 he was Principal of Hertford College where he is now a Senior Research Fellow.
See page on Hertford College website