Canaday's inaugural column and subsequent articles criticizing this style provoked a much-publicized letter to "The New York Times" signed by 49 of the nation's leading art figures, who denounced Canaday as an agitator. "I have trouble vis-à-vis Canaday," one artist wrote. "What he thinks of me, he can print, while what I think of him is unprintable." Other artists and critics, however, championed him as an honest and articulate observer of the art scene, which continued to provide ample targets for his barbed wit over the years. In addition to writing for the "Times", Canaday published a number of influential books, notably "Mainstreams of Modern Art: David to Picasso" (1959), winner of the Athenaeum Literary Award and a popular art history textbook for many years. His experiences as a critic provided the subject matter of two books, "Embattled Critic: Views on Modern Art" (1962) and "Culture Gulch: Notes on Art and Its Public" in the 1960s (1969). He also wrote "Keys to Art", with Katherine H. Canaday (1963), "The Lives of the Painters" (1969), "Baroque Painters" (1972), "Late Gothic to Renaissance Painters" (1972), "Neoclassic to Post-Impressionist Painters" (1972), "My Best Girls: 8 Drawings" (1972), "The New York Guide to Dining Out in New York" (1972), "The Artful Avocado" (1973), "Richard Estes: The Urban Landscape" (1979), "What is Art? An Introduction to Painting, Sculpture, and Architecture" (1980), and "Ben Shahn, Voices and Visions" (1981). In the 1940s and 1950s, under the pen name Matthew Head, Canaday wrote seven crime novels with such titles as "The Smell of Money" (1943), "The Congo Venus" (1950), and "Murder at the Flea Club" (1957). Drawing in part on his experiences in the Congo, he set three of his mysteries in Africa, and they were heralded by one critic as subtly foreshadowing a time of change on the African continent. In 1974, Canaday stepped down from his post as art critic in order to devote more time to writing books, although he continued to write restaurant reviews for the "Times" until his retirement in 1977.