Walt Whitman's poetry and prose celebrate themes of individualism and the collective human experience. He championed the human spirit and its connection to nature and society in works like Leaves of Grass. His style is marked by free verse and a conversational tone, embracing themes of democracy, love, and transcendentalism. Whitman explored the significance of the self while emphasizing a sense of brotherhood among all people. His works often reflect an optimistic view of humanity's potential, promoting ideas of unity and the beauty of life's diverse experiences.