Walt Whitman - Leaves of Grass is a poetry collection by the American poet Walt Whitman (1819?1892). Though the first edition was published in 1855, Whitman spent most of his professional life writing and re-writing Leaves of Grass,[1] revising it multiple times until his death. This resulted in vastly different editions over four decades?the first a small book of twelve poems and the last a compilation of over 400 poems.