'Tread softly because you tread on my dreams' is one of the most well-known and repeated lines of poetry ever written. Less haunting, but still so relevant: 'Life is a long preparation for something that never happens.' W B Yeats was one of the foremost figures of 20th century literature. Winner of a Nobel prize, he was also a political figure and, as is evident from his earlier work, fascinated by Irish folklore and the occult. He was also deeply affected by the First World War and the Anglo-Irish and Irish civil wars. It is a testament to the greatness of Yeats' poetry that he attempts to bear witness to these emotional and historical forces.