The key word in this question is "first." Whitman first published the poem in 1855, but he edited it and published new versions until his death in 1892. Over nearly four decades, the volume expanded from a dozen poems to more than 400.

Passage adapted from "Song of Myself" in Leaves of Grass by Walt Whitman, ln.1-8 (1855)

“O Captain! My Captain” by Walt Whitman was first published in 1865. “The Road Not Taken” by Robert Frost was first published in 1916. “Because I Could Not Stop For Death” by Emily Dickinson was first published in 1890. “Middle Passage” by Robert Hayden was first published in 1945, and “Burnt Norton” by T.S. Eliot was first published in 1936.

Passage adapted from "Song of Myself" in Leaves of Grass by Walt Whitman, ln.1-8 (1855)

“Water, water everywhere, nor any drop to drink" is from Samuel Taylor Coleridge's "Rime of the Ancient Mariner" (1834 version),  “Hope is the thing with feathers” is from the Emily Dickinson poem of the same name published in 1891, “Two roads diverged in a wood, and I— / I took the one less traveled by” is from Robert Frost's "The Road Not Taken" (1916), and  “How do I love thee? Let me count the ways” is from Elizabeth Barrett Browning's "Sonnet 43" (1850).

"Do I contradict myself? Very well, then I contradict myself, I am large, I contain multitudes" was taken from the 1892 edition of Leaves of Grass. 

Passage adapted from "Song of Myself" in Leaves of Grass by Walt Whitman, ln.1-8 (1855)

“The Raven” by Edgar Allan Poe was first published in 1845. “A Choice” by Paul Laurence Dunbar was first published in 1913. "I wandered lonely as a cloud" by William Wordsworth was first published in 1807. “Paul Revere’s Ride” by Henry Wadsworth Longfellow was first published in 1860.

Passage adapted from "Song of Myself" in Leaves of Grass by Walt Whitman, ln.1-8 (1855) "I Sing the Body Electric" was published in the same volume.

Anne Sexton's poem "Sylvia's Death" deals with the death of fellow poet Sylvia Plath.

The poem is by Gwendolyn Brooks, who was the first African American poet to win the Pulitzer Prize. Brooks experimented with poetic form throughout her career, but her poetry is often concerned with the urban poor of the area of Chicago in which she lived for much of her life. This poem is a favorite of the Lit GRE's and it is extremely short, so you should make it a point to be able to recognize it on first sight.

The poet described is Edward Estlin Cummings, usually known as e. e. cummings. In addition to his poetry, Cummings was known for his paintings, plays, novels and essays.

The poet in question is Allen Ginsberg, a leading figure in the counterculture movement. His most famous work, “Howl,” gave voice to previously unheard minorities and spoke against war, materialism, consumerism, homophobia, and various forms of repression. Its opening lines are frequently quoted, although “Howl” was often censored because of its depictions of homosexual and heterosexual sex acts.

The poet is Sylvia Plath, wife of the British poet Ted Hughes and an important figure in the genre of confessional poetry. Plath’s work is marked by body- and nature-based imagery, depictions of mental illness, and seemingly mundane details from everyday life.

The poem, broken into 13 fractured, imagistic sections, was written by American poet Wallace Stevens. Stevens was a leading figure in the American modernist poetry world, and in 1955 he won a Pulitzer for his work. Stevens’ work is marked by a preoccupation with intellectual themes and ideas about human consciousness. Some of his best-known poems include “The Emperor of Ice Cream,” “Anecdote of the Jar,” “The Idea of Order at Key West,” and “Sunday Morning,” as well as “Thirteen Ways of Looking at a Blackbird.”