The Man Who Was Thursday: A Nightmare is a novel by G. K. Chesterton, first published in 1907. The book is sometimes referred to as a metaphysical thriller In Edwardian era London, Gabriel Syme is recruited at Scotland Yard to a secret anti-anarchist police corps. Lucian Gregory, an anarchistic poet, lives in the suburb of Saffron Park. Syme meets him at a party and they debate the meaning of poetry. Gregory argues that revolt is the basis of poetry. Syme demurs, insisting the essence of poetry is not revolution but law. He antagonises Gregory by asserting that the most poetical of human creations is the timetable for the London Underground.