Increasing population and development pressures have precipitated the need for more and more accurate methods of recording and interpreting traces of human activity across rural landscapes and urban contexts. On the landscape scale, and in the context of the devastating effect of intensive, mechanised farming on archaeological monuments in the countryside, aerial photography has been the mainstay of archaeological reconnaissance and survey since WWII. It has been a major source for the mapping of ancient landscapes; in a Roman context one thinks particularly of the great increase in knowledge of military sites, such as St Joseph's work in Britain, and what has been learned about the development of frontier systems across the Empire, for example the work of Bewley and Kennedy in Jordan and of the pioneer aerial photographer, Père Poidebard, in Syria. Aerial survey has also been a major source of information for the development internationally of Sites and Monuments Records (SMRs) (now Historic Environment Records [HERs] in the UK) and thus predicting the potential impact of mineral extraction and development in general on archaeological remains in the countryside, and planning appropriate mitigation.

But aerial survey is intrinsically broad brush and works best on arable land in the right conditions, where complete sites and landscapes can be revealed in astonishing detail, leaving the need to find other ways of mapping sites in less susceptible environments such as pasture and woodland. Given the costs of archaeological fieldwork and publication it has become necessary to provide more and more sophisticated information to define with greater clarity the extent and scope of settlements and landscapes threatened by development. Here the development of geophysical survey over the last 30–40 years is playing a major role and the range of techniques and their efficacy is constantly being improved. Airborne lidar, magnetometry, resistivity, ground-penetrating radar (GPR), all have a role to play. A clear message of this volume, as the editors carefully develop in their respective introductory chapters, is that an approach to survey which is flexible and able to apply multiple methodologies to determine what works best is the way forward; no one method can be relied upon to give a ‘full’ picture. Indeed the various forms of remote sensing available to the archaeologist do only provide images; they do not necessarily give insight into chronology and change over time.

The majority of the fourteen contributions to this collection are concerned with geophysics and showcase research from six Roman urban sites: Carnuntum (Austria), Mariana in Corsica (France) (two papers), Gabii, Portus and Trea in Italy. Beginning the section on ‘Integrating Geophysics’ is the study of a much earlier site, the second millennium b.c. Pharaonic town of Amara West in Northern Sudan, demonstrating the efficacy of magnetometry deploying fluxgate gradimeters for mapping in sandy, desert environments. With the Roman-period sites we can see that, where magnetometry did not work well for Mariana, GPR provided a clear plan of part of the street grid of the colonia and some of the constituent buildings within individual insulae. From a position where, at the outset, very little was known of the extent and basic plan of the colonia, invaluable information has been obtained from the survey to define and characterise the settlement and inform development control. Development pressures are also driving the surveys of the legionary fortress of Carnuntum, its canabae and hinterland some 40 km south-east of Vienna. Here integration of aerial photography and excavation data has provided a remarkable map of the canabae of the fortress and its environs over several square km (fig. 9.3). Complementing the broader picture (but frustratingly its position not located on fig. 9.3), a smaller area of 5ha, not susceptible to aerial photography, was surveyed by magnetometry identifying dense settlement within a network of streets and lanes and indications of a substantial building. The latter was then further investigated using ground-penetrating radar to produce with remarkable detail the ground plan of the civil forum (fig. 9.5). The three Italian examples provide further examples of different approaches. At Gabii conditions were right for fluxgate gradiometry which added extensive and substantial new information on the plan of the town. However, at Trea artefact survey focused on sample areas of the town where aerial photography had been very helpful in providing basic knowledge of the overall plan (fig. 12.10), but with a relatively disappointing contribution from geophysics. Finally, where understanding the geomorphology and sedimentary environment is so important in the development of archaeological survey, the results of recent work at Portus and its hinterland are presented. On the one hand, and in narrow focus, the integrated results of the application of a range of techniques – fluxgate gradiometry, resistivity, GPR, Electrical Resistivity Tomography (ERT) – on the remains of the Palazzo Imperiale are presented, the strengths and weaknesses of each technique evaluated; on the other, in the landscape context, both large scale through the interpretation of archival aerial photography extending southwards to the Tiber and more selectively over some 360ha of the Isola Sacra, where fluxgate gradiometer survey has revealed important information on both major and minor canal systems.

Reminding us that, while aerial and geophysical survey can tell us so much about plan and landscape, they cannot contribute much to chronological frameworks, is a group of three valuable papers on surface collection. This was the principal methodology applied to ancient townscapes and landscapes in the 1970s and 80s, eventually giving way in popularity and cost to geophysical prospection. While the frequency of its application may have declined, its value as a survey method remains undiminished. The meticulous survey of the hinterland of Knossos (Greece, Crete) provides the context for a thoughtful review of methodology such as sampling strategies and the various issues which affect the recovery of material, while the chapter on Philosophiana-Sofiana (Italy, Sicily) economically presents the key results of survey across the walled town and its immediate hinterland to reveal the changing patterns of occupation and discard between the Hellenistic period and the thirteenth century. In contrast, the case study drawing on material collected from Sagalassos (Turkey) and its environs works through the potentiality of the total collected assemblage for understanding better the changing dynamics of the town including intensities of economic activity and changing relative prosperity as reflected in the ceramic record.

The editors are to be congratulated on an important collection of essays on the issues surrounding archaeological survey in the ancient world, the effectiveness of the various techniques now available to archaeology, and the necessity of applying a flexible approach to obtain best value from the methods which work effectively to answer the questions being addressed. It should be essential reading to all those learning about geophysics and archaeology as well as those contemplating a programme of archaeological survey in the field.