This paper brings up to date accounts of discoveries by air reconnaissance in the field of Romano-British studies already published in this Journal (JRS XLI, XLIII, and XLV). In the last few years nearly every major Roman site in Britain has been repeatedly reconnoitred from the air in a yearly course of flights especially planned for the purpose of research. The body of information thus obtained shows that even air survey conducted over several successive years does not exhaust the possibilities of acquiring new knowledge at places already known, while discovery of sites hitherto unrecognized continues apace. The incidence of the discoveries, however, proves to vary. Scrutiny of military sites in the area of Hadrian's Wall and its hinterland, which yielded so much information in the decade 1945–55, has in the last three years added comparatively little to the record.