Among his books is "the best introduction to the art of Leonardo da Vinci ever written". Piper singles out, in addition to the Leonardo monograph, Clark's "Piero della Francesca" (1951), "The Nude" (1956, based on his Mellon lectures in Washington in 1953), and "Rembrandt and the Italian Renaissance" (1966 from his Wrightsman lectures in New York). The critic Jackie Wullschlager wrote in 2014 that it was as a writer rather than a collector that Clark excelled: "unrivalled since Ruskin for lucidity, erudition, moral conviction". James Hall, in "The Guardian", expressed a similar view, calling Clark "the most seductive writer on art since Ruskin and Pater ... Today, when most art historians write as joylessly as lawyers and accountants, such verve is sorely needed."