Leaves of Grass is a poetry collection by American poet Walt Whitman. Though it was first published in 1855, Whitman spent most of his professional life writing, rewriting, and expanding Leaves of Grass until his death in 1892. Six or nine individual editions of Leaves of Grass were produced, depending on how they are distinguished. This resulted in vastly different editions over four decades. The first edition was a small book of twelve poems, and the last was a compilation of over 400.

American poetry refers to the poetry of the United States. It arose first as efforts by American colonists to add their voices to English poetry in the 17th century, well before the constitutional unification of the Thirteen Colonies. Most of the early colonists' work was similar to contemporary English models of poetic form, diction, and theme. However, in the 19th century, an American idiom began to emerge. By the later part of that century, poets like Walt Whitman were winning an enthusiastic audience abroad and had joined the English-language avant-garde.