This is a monograph and early catalogue raisonné of all paintings by Opie known to the author. Although Opie kept a ledger of all of his paintings after 1781, the author notes that he could not locate this ledger in compiling his catalogue raisonné. Consequently, there may be authentic works not listed in this catalogue. In addition to the catalogue, the publication includes lists of pictures exhibited during Opie's lifetime and excerpts of two letters by the artist.