Walt Whitman was an American poet, essayist, and journalist, best known for his collection of poetry, "Leaves of Grass." He is often considered one of the most influential poets in the American literary canon. Whitman's work is characterized by its celebration of the individual, nature, and the human experience. His writing style is known for its free verse and expansive, lyrical language. Whitman's poetry often explores themes of democracy, spirituality, and the interconnectedness of all living things. His work has had a lasting impact on American literature and continues to be studied and celebrated around the world.