This is not the first book in Fforde's series starring literary detective Thursday Next, and it sees her struggling to regain memories of a husband who's been erased from history, coping with the transition from the real world to the world inside fiction, trying to help out a detective novel due for demolition and solving several nasty murders into the bargain.
This is nothing if not a very postmodern novel, stealing liberally from the greats of the past, making fun of them when Fforde feels like it and playing the limitations of the average genre novel for laughs and serious points in turn. Mostly, the humour is the sort of thing that appeals to those with at least a reasonable familiarity with literature. One minor subplot, for example, revolves around the theft of all the punctuation from the second half of James Joyce's Ulysses, while the failure of Jurisfiction Agent Godot to show up for roll call is something of a running joke. It's the sort of thing where, if you take literature very seriously, you'll hate what he's done with your favourite character, but otherwise you'll be too busy laughing to object.
That's not to say it's without problems. Mostly, they come in the form of the footnotes. The idea of footnotes being the equivalent of phones in Fforde's literary universe is a clever one, but means that you spend half your time jumping to the bottom of the page, and often for what amounts to crossed lines and spam. Half a chapter is told in this way, and it's almost impossible to judge what order to read everything in. Also, if you're new to the series, the strangeness of it can be jarring at first, particularly as Fforde has taken at least as many liberties with real world history as with the fictional side of things.
On the whole though, this is a wonderfully well done, funny, clever book that should appeal to anyone who's ever wondered if the characters in Dickens ever wander off while the author's eye isn't on them.