For me there is no contest, the answer has to be one of Jasper Fforde’s Thursday Next books and you might as well begin with the first, “The Eyre Affair”. For in this book Thursday enters into Charlotte Bronte’s “Jane Eyre.”
In an alternative 1985, the Crimean war still rages, dodos are regenerated in home-cloning kits and everyone is deeply disappointed by the ending of “Jane Eyre”. Characters from novels are being kidnapped and Jane is missing. Thursday Next, a SpecOp for literary crimes, who lives in Swindon, finds a way into the book to solve Jane’s disappearance while at the same time working out who actually wrote Shakespeare’s plays.
This is my kind of humour, filled with literary references and quirky notions.