It is very difficult to classify "The Man Who Was Thursday." It is possible to say that it is a gripping adventure story of murderous criminals and brilliant policemen; but it was to be expected that the author of the "Father Brown" stories should tell a detective story like no-one else. On this level, therefore, "The Man Who Was Thursday" succeeds superbly; if nothing else, it is a magnificent tour-de-force of suspense-writing. However, the reader will soon discover that it is much more than that. Carried along on the boisterous rush of the narrative by Chesterton's wonderful high-spirited style. You will soon see that you are being carried into much deeper waters than you planned on; and the totally unforeseeable denouement will prove, as it has for thousands of others since 1908 when the book was first published, an inevitable and moving experience, as the investigators finally discover who Sunday is.