A self-declared Objectivist poet, George Oppen was greatly influenced by William Carlos Williams, Louis Zukofsky, and Charles Reznikoff. His place among his contemporaries was established in 1931 when Zukofsky chose several of Oppen's poems for an "Objectivist" issue of Poetry magazine.

During the Depression, Oppen and his wife moved increasingly to the political left, becoming social activists and joining the Communist party in 1935. During this period his poems appeared only in small journals, and he eventually gave up writing for more than two decades. After serving in World War II, Oppen returned to New York and found that his politics made him a target of the House Un-American Activities Committee, forcing him to flee with his wife to Mexico in 1950.

Oppen revived his poetic career when he returned to the United States in 1958. In 1962, New Directions published Oppen's second book of poetry, The Materials, which was followed by This in Which. Published in 1968 and awarded the Pulitzer Prize, Of Being Numerous was Oppen's fourth and most critically acclaimed collection.

The title poem, widely considered his masterpiece, is a sequence of forty sections that examines questions of singularity within a diverse and crowded world. The poem embodies his terse, powerful lines and strong, focused syntax. Williams once said of Oppen: "He has never varied in his direct approach to the word as the supreme burden of the final poetic image."