GKC comments on his TMWWT

Spoiler Warning: If you have NOT as yet read Chesterton's The Man Who Was Thursday I strongly advise you not to bother reading this post. It does not exactly "give away" the ending, but it is better for you to read the book first, and then these commentaries. This is a general rule I urge on all, as there is no worse sin in literature than giving away the ending to a mystery...

Dr. Thursday

I happened to dedicate to Mr. Bentley, in those distant days, a book called "The Man Who Was Thursday"; it was a very melodramatic sort of moonshine, but it had a kind of notion in it; and the point is that it described, first a band of the last champions of order fighting against what appeared to be a world of anarchy; and then the discovery that the mysterious master both of the anarchy and the order was the same sort of elemental elf; who had appeared to be rather too like a pantomime ogre. This line of logic, or lunacy, led many to infer that this equivocal being was meant for a serious description of the Deity; and my work even enjoyed a temporary respect among those who like the Deity to be so described. But this error was entirely due to the same cause; that they had read the book but had not read the title-page. In my case, it is true, it was a question of a sub-title rather than a title. The book was called "The Man Who Was Thursday: a Nightmare." It was not intended to describe the real world as it was, or as I thought it was, even when my thoughts were considerably less settled than they are now. It was intended to describe the world of wild doubt and despair which the pessimists were generally describing at that date; with just a gleam of hope in some double meaning of the doubt, which even the pessimists felt in some fitful fashion. The matter was fully stated in some rather bombastic verses which I addressed to Mr. Bentley at the time; and I may be excused for mentioning them here in this connection; as a salutation and a memorial of old times.
{GKC, ILN June 13, 1936 - note, this was his second-last essay!]