- Principal, Hertford College, Oxford (from 2005 to 2011)
- Quondam Fellow, All Souls College (from 2005)
- Lecturer in Historical Demography and Fellow, All Souls College (from 1991 to 2005)
- Lecturer in Biological Anthropology, University College London (from 1980 to 1990)
- Oil Demand Analyst, Shell UK Ltd (from 1979 to 1980)
- Postgraduate, Churchill College, Cambridge (from 1975 to 1979)
- Undergraduate, Hertford College, Oxford (from 1972 to 1975)
- The Field and the Forge: Population, Production, and Power in the pre-Industrial West (New York: OUP, 2003)
- Death and the Metropolis: Studies in the Historical Demography of London, 1670–1830 (New York: CUP, 1993)
- Chairman, Animals in Science Committee (from 2011)
- Member of the International Union for the Scientific Study of Population