Leaves of Grass (1855) is a poetry collection by the American poet Walt Whitman. Among the poems in the collection are "Song of Myself," "I Sing the Body Electric," and in later editions, Whitman's elegy to the assassinated President Abraham Lincoln, "When Lilacs Last in the Dooryard Bloom'd." Whitman spent his entire life writing Leaves of Grass, revising it in several editions until his death.
Leaves of Grass has its genesis in an essay called The Poet by Ralph Waldo Emerson, published in 1845, which expressed the need for the United States to have its own new and unique poet to write about the new country's virtues and vices. Whitman, reading the essay, consciously set out to answer Emerson's call as he began work on the first edition of Leaves of Grass. Whitman, however, downplayed Emerson's influence, stating, "I was simmering, simmering, simmering; Emerson brought me to a boil".