My research has been wide-ranging in chronological and geographical terms, as well as in subject matter. There are strong unifying trends running through and I am essentially a specialist in the archaeology of the Roman empire. I am an active field archaeologist and have organised projects in Britain, Italy, Libya, Tunisia and Jordan.
A significant component throughout my career to date has been the study of Roman Africa. My main contributions to the advancement of Roman Africa studies have been in terms of study of rural settlement, farming technology and the economy; urbanism and the urban economy; post-colonial approaches to the impact of Rome; the evolution of the Roman military frontiers and, latterly, the study of native society beyond those frontiers. I was a major author of the final reports on the UNESCO Libyan Valleys Survey and helped initiate work in 1990 at an important Tunisian harbour site called Leptiminus, leading to three published volume of reports.
Recently, the Fazzan Project in Libya has taken me beyond the boundaries of the Roman empire to research the Saharan heartlands of an important people called the Garamantes. Three volumes arising from this work have been published so far, with a fourth in progress. This Sahara work has now entered further phases as the Desert Migration Project the Peopling the Desert Project, the Ghadames Archaeological Survey and the Trans-Sahara Project. A second research strand developed from my Oxford-based post-doctoral research into olive cultivation in the Roman world and the production of olive oil and its trade. This has fed in to a recurrent interest in the Roman economy
A third area of research has been rural field survey, where I have published final reports on multi-period work near Rieti in Italy, in Libya and in Jordan (Wadi Faynan).
A further area is imperialism and I have written two books in recent years (one on Britain in the Roman empire and the other a set of essays on aspects of imperialism in the Roman world), where I have published explored new approaches to power and identity.