In his later work, he experimented with more open forms, beginning with "The Bourgeois Poet" (1964) and continuing with "White-Haired Lover" (1968). His interest in formal verse and prosody led to his writing multiple books on the subject including the long poem "Essay on Rime" (1945), "A Bibliography of Modern Prosody" (1948), and "A Prosody Handbook" (with Robert Beum, 1965; reissued 2006). His "Selected Poems" appeared in 1968. Shapiro also published one novel, "Edsel" (1971) and a three-volume autobiography titled "Poet" (1988–1990).