This work, in nine chapters, is a retrospective analysis of ditched rural structures (dating from Prehistoric to Gallo-Roman times) which have been traced since 1975 by aerial surveys over northern Brittany. As well as detailing aerial surveying techniques and archaeology, the study serves also as a comparative framework for similar structures located on both sides of the Channel. Aerial observation is particularly valuable as a means of detecting such remains, and this volume presents a detailed analysis of sites, combining text, graphics and statistics with numerous maps of the areas under study.