A strange, nightmarish novel, excellently drawn and very fast paced.
It is not just the title that suggests that all the characters are sleepwalking in a vivid dream. Barnes convincingly captures the narrative voice of the lunatic convinced that he is sane. The author is obviously having a lot of fun in his Victorian London, relishing his menagerie of grotesques and characters with a few deftly drawn strokes.
He manages the trick of making us sympathise with all of them as the points of view slip and slide - and like all tricksters - or dreams, you are never quite sure whether you are really on firm ground. His creation of the "Prefects" are an absurdity that shouldn't work but, very chillingly, do.
It ends with an enigma and like most dreams, it has that narcotic quality that jumbles images and characters and incidents while still making sense and forming a strong narrative whole. When you wake, you are left with a lingering sense of wanting to go back for more, even as you realise that it is slipping just beyond your grasp.