Leaves of Grass is the main work of Walt Whitman, one of the most significant American poets. The first version of this cycle consisted of untitled poems and was self-published by Whitman in 1855. Over the next 36 years, the collection was repeatedly revised and significantly expanded (from initially twelve to almost 400 poems of varying lengths, often in the form of poem cycles, in the ninth edition of 1892). Walt Whitman (1819-1892) was an American poet. He is considered one of the founders of modern American poetry and thus one of the most influential American poets of the 19th century, whose work remains of great literary significance in later times. His most famous work is his life's work, Leaves of Grass.