William Blake's Illustrations of the Book of Job primarily refers to a series of twenty-two engraved prints (published 1826) by Blake illustrating the biblical Book of Job. It also refers to two earlier sets of watercolours by Blake on the same subject (1806 and 1821). The engraved Illustrations are considered to be Blake's greatest masterpieces in the medium of engraving,[1][2] and were also a rare commercial and critical success for Blake.