William Butler Yeats was an Irish poet, playwright, and one of the foremost figures of 20th-century literature. He was a key figure in the Irish Literary Revival and co-founded the Abbey Theatre. Yeats' poetry is known for its lyrical beauty, symbolism, and exploration of Irish mythology and folklore. He was awarded the Nobel Prize in Literature in 1923 for his profound poetic works, which continue to be celebrated for their enduring impact on literature and culture.