Walt Whitman (1819 - 1892) is one of the greatest American poets. Leaves of Grass was published in 1855, which he added to and reshuffled throughout his life.
Whitman, the great poet, has meant so much to me. Whitman the one man breaking a way ahead. Whitman the one pioneer . . . Ahead of Whitman, nothing. Ahead of all poets, pioneering into the wilderness of unopened life, Whitman. Beyond him, none. -D. H. Lawrence