[1] Sullivan decided to concentrate on the emerging field of graphic design and book illustration, which was flourishing at the end of the nineteenth century.

By the end of the decade Sullivan's designs were in high demand, leading to the publication of his most ambitious work, an illustrated edition of Thomas Carlyle's Sartor Resartus, published in 1898.

Sullivan adapted his style to use the faux-Rococo techniques he had developed in his play-illustrations in order to combine them with bizarre images of strange fantastical figures, drawing on the genre of the grotesque.

He used the same combination of Rococo and Grotesque to emphasise the violence erupting into the decorative world of Louis XVI and Marie Antoinette's court.

Sullivan also used his skills of satire in 1916 in a collection of wartime designs called the Kaiser's Garland, which attack Prussian militarism.