Hillforts are among the most dramatic and visually striking of prehistoric monuments in the British Isles. Dorset, in southern England, is particularly rich in these Iron Age earthwork enclosures, with over 30 examples being so far recorded, including the internationally famous sites of Maiden Castle, Hod Hill, Badbury Rings and Hambledon Hill. Many have been the subject of archaeological investigation, such as the excavations conducted at Maiden Castle in the 1930s by Tessa and Mortimer Wheeler, but few have, to date, been intensively examined. This volume sets out the results of a detailed programme of non-intrusive geophysical survey conducted across the Dorset hillforts, generating detailed subsurface maps of archaeological features, in the hope of better resolving the phasing, form and internal structure of these iconic sites. The dataset presented here not only helps to change our perception of what hillforts were, how they functioned and what went on within them, but also provides a way of assessing their longevity, reconsidering how they were perceived and reused in subsequent periods. Given the oft-cited association between the Dorset enclosures and the Durotriges tribe, who are thought to have occupied the area in the Later Iron Age, serious consideration is also for the first time given to the belief that hillforts formed the focus of conflict between the native tribes and the armies of imperial Rome in the first century AD.