At first, The Man Who Was Thursday seems no more than a detective story that also has both poetry and politics, as well. But it soon becomes a mystery that grows more mysterious, until it is nothing less than the mystery of creation itself. This is Chesterton's most famous novel. Never out of print since it was first published in 1908, critics immediately hailed it as "amazingly clever," "a remarkable acrobatic performance," and "a scurrying, door-slamming farce that ends like a chapter in the Apocalypse." One reviewer described how he had read it in one sitting and put it down, "completely dazed."

"This book is Chesterton at his best. Every scene is perfect. Every line is a gem." (The American Chesterton Society)

"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." (World Wide School Library)