Catalogue is arranged alphabetically by location. Works the author saw only in photographs are indicated with asterisks. Individual entries also include information on studio copies and other versions after original works. The catalogue lists 77 authentic works. There are separate catalogues of doubtful works; copies after lost originals; lost works; and rejected attributions. The catalogue illustrates a painting of St. Jerome that was discovered as the book went to press, and therefore not discussed in the catalogue.