The Man Who Was Thursday: A Nightmare is a novel by G. K. Chesterton, first published in 1908. The book is sometimes referred to as a metaphysical thriller. Its importance was recognized in its later revival in paperback by Ballantine Books as the thirty-second volume of the celebrated Ballantine Adult Fantasy series in July 1971.
Although it deals with anarchists, the novel is not an exploration or rebuttal of anarchist thought; Chesterton's ad hoc construction of "Philosophical Anarchism" is distinguished from ordinary anarchism and is referred to several times not so much as a rebellion against government but as a rebellion against God.
The novel has been described as "one of the hidden hinges of twentieth-century writing, the place where, before our eyes, the nonsense-fantastical tradition of Lewis Carroll and Edward Lear pivots and becomes the nightmare-fantastical tradition of Kafka and Borges."
As part of Project Gutenberg, the book is available for download at http://www.gutenberg.org/etext/1695.