G. K. Chesterton's surreal masterpiece is a psychological thriller that centers on seven anarchists in turn-of-the-century London who call themselves by the names of the days of the week. Chesterton explores the meanings of their disguised identities in what is a fascinating mystery and, ultimately, a spellbinding allegory.
As Jonathan Lethem remarks in his Introduction, The real characters are the ideas. Chesterton's nutty agenda is really quite simple: to expose moral relativism and parlor nihilism for the devils he believes them to be. This wouldn't be interesting at all, though, if he didn't also show such passion for giving the devil his due. He animates the forces of chaos and anarchy with every ounce of imaginative verve and rhetorical force in his body.
In his final essay, Christopher Hitchens wrote: "As to the durability or importance of GKC as a fictionist: the late Sir Kingsley Amis once told me that he reread The Man Who Was Thursday every year, and on one of his annual visitations wrote a tribute. That novel, with its evocation of eeriness and solitude, and its fascination with anonymity, has been credited by some with a share of influence on Franz Kafka."
