Ode to a Nightingale is a poem by John Keats that expresses the beauty of nature and the transience of human life. Through the imagery of the nightingale's song, Keats explores themes of mortality, longing, and the desire for transcendence, which are central to Romantic literature. The poem contrasts the ideal beauty of the nightingale with the harsh realities of human existence, reflecting a deep yearning for escape from pain and suffering.