The American Romantic Period (1820-1860) emphasized intuition, imagination, and individualism, showcasing authors like Washington Irving, whose works include 'The Legend of Sleepy Hollow' and 'Rip Van Winkle.' Transcendentalism, a literary and philosophical movement, encouraged personal spirituality and intuition, influencing figures like Ralph Waldo Emerson and Henry David Thoreau. Dark Romanticism, a subgenre marked by horrific themes and psychological effects, included notable works by Edgar Allan Poe and Nathaniel Hawthorne, highlighting the inherent evil within humanity.