This is one strange book. It starts out as a standard Victorian genre novel - a gripping spy thriller, but then, as the subtitle indicates, turns into a spiritual fever dream. Along the way, Chesterton's wit makes it a pleasure to read (even when you're not sure what's going on). One little gem: "Thieves respect property. They merely wish the property to become their property that they may more perfectly respect it." It reminded me in places of "The Master and Margarita" because of the way the writers are able to evoke exactly the feeling of being trapped in a nightmare.