Walt Whitman (1819-1892) was an American poet, essayist, and journalist, widely regarded as one of the most influential figures in American literature. Born in Long Island, New York, Whitman's work broke away from traditional forms and celebrated individuality, democracy, and the human spirit. His landmark collection Leaves of Grass, first published in 1855, is known for its free verse, its embrace of the body and the senses, and its celebration of the interconnectedness of all life. Whitman's poetry explores themes of nature, self-expression, love, and death, and he is often hailed as the poet of America's democratic ideals. His work challenged societal norms and influenced generations of poets and writers, cementing his place as a defining voice of 19th-century literature.