This chapter discusses the use of dictionaries and books of reference as a motif and a formal device in American poetry, particularly in the avant-garde stream, from Zukofsky to the Language poets, with special reference to the work of Ron Silliman and Tina Darragh. It distinguishes long poems in the Whitman tradition, which attempt to comprehend the world in the form of lists and extended descriptions, often using alphabetical orderings or other kinds of organisation similar to dictionaries, and smaller works of visual poetry able to subvert the notion of definition in a dictionary.