The central plot of The Eustace Diamonds (1872) involves the theft and ultimate discovery of a diamond necklace - the Eustace family heirloom. A splendid sense of the absurd permeates the novel and allows Trollope to examine "truth" in may contexts and at many levels of seriousness. Lizzie's unscrupulous lies do not prevent her final exposure, and it is, as Stephen Gill says in his Introduction, "this honesty, this clarity of vision that places Trollope with the greatest social novelists of the nineteenth century, with Dickens, Thackeray, and George Eliot."

In spite of its prevailing comedy, this rich and subtle novel reveals a sombre vision of the world, representing the mature Trollope's growing feelings about class structure and social change in England.