Leaves of Grass is a groundbreaking collection of poetry by Walt Whitman, first published in 1855 and continually revised throughout his life. The work is celebrated for its innovative style, themes of individualism, and deep connection to nature, which resonate with the ideals of American Romanticism. Whitman's poetry emphasizes the importance of personal experience and the beauty of the American landscape, making it a central text in understanding the cultural and literary movements of the time.