The publication of these two volumes completes Neal and Cosh's corpus of all the decorated mosaics known from Roman Britain, the first complete catalogue of mosaics from any of the Roman provinces. It is a tremendous achievement, the culmination of almost ninety years' combined work on the part of the authors, going back to 1959 when David Neal painted his first mosaic at Verulamium. The statistics are mind-boggling: the four volumes of the corpus list nearly 2,000 mosaics (double the number known before the project started), from about 500 sites, with nearly 3,000 illustrations. Just to compile this much material would be a heroic task; the fact that the authors have also painted hundreds of the mosaics tessera by tessera is little short of astonishing.