This is Jasper Fforde's 7th book, the fifth book about Thursday Next.
There are two ways to read a Jasper Fforde novel;
1) just read them straight, as the detective novels they are supposed to be, albeit some very strange circumstances in which Thursday finds herself in, or
2) If you have read widely, the literary allusions Fforde makes are subtle but funny.
Either way the novels are brilliant.
I would have been very confused if I hadn't read the previous books, although the title implies it is a sequel, and I do wonder how many people will have been able to make sense of the book if they hadn't read any of the other books featuring Thursday Next.
That aside, I loved the book. I won't try to explain it, other than, imagine a world where there wasn't just MI5, MI 6, etc, but other things needed investigating, like the true running of time, that fiction ran true to form, mythical creatures weren't mythical but real, and you are part way into the world of Thursday Next.
Fourteen years after she pegged out at 1988 SuperHoop, Thursday Next is grappling with a recalcitrant new apprentice, the death of Sherlock Holmes and the inexplicable departure of comedy from the once hilarious Thomas Hardy novels.
Her idle sixteen-year-old son would rather sleep all day than save the world from imminent destruction, the government has a dangerously high stupidity surplus, and the Stiltonista Cheese Mafia are causing trouble for Thursday in her home town of Swindon.
Then things begin to get bad. As reality Book Shows look set to transplant Reality TV Shows and Goliath invent a trans-fictional tourist coach, Thursday must once again have her wits about her as she travels to the very limits of acceptable narrative possibilities to rescue the reading experience from almost certain destruction....
http://www.jasperfforde.com/
One last thing about this book, which you will find on Jasper Fforde's website. The first editions have the footnotes missing, most have been recalled. There was a downloadable copy of them on the website.
Jasper Fforde has left the ending open, so it is clear that he will return to Thursday Next....or will he?