The universe of The Eyre Affair, the first of (so far) five Thursday Next books, plays very well to my sensibilities. The year is 1985, England is enmeshed in a thirteen-decade-long quagmire in the Crimea, the People's Republic of Wales sits right next door, dirigibles are the preeminent mode of arial transportation, genetically re-created dodos and great auks are popular pets, and classic literature somehow occupies a far higher place in pop culture consciousness than movies and TV. The scene where Richard III is performed for a rowdy crowd who treat it with the same appreciation that greets Rocky Horror in our universe ought to warm the cockles of all Shakespeare-loving hearts.
For her first book, SpecOps operative and main protagonist Thursday Next must deal with criminal schemes that revolve around the following basic facts about how this universe operates:
1) If you alter a text, the alterations will instantaneously spread to every text that was copied from that one. So it's easy to see why original literary manuscripts are guarded against criminal mischief.
2) The division between "real life" and works of fiction is a permeable one. People from "real life" regularly go vacationing in classic works of 19th-century literature; similarly, fictional characters (and devices) can be brought into the "real world".
Additionally, fictional characters are fully conscious of being fictional. Rochester from Jane Eyre delivers a particularly moving account of how life as a character is in many ways superior to life as a real person.
Which brings me to my unfortunate confession: I've never read Jane Eyre. I suppose Fforde's book is perfectly comprehensible even if you're totally ignorant of the original story, but I went to Wikipedia to catch up on what I'd missed.
There are several marvelous little details that went into this world but never actually become directly relevant to the story. The Eyre Affair was published in 2001 but set in 1985; that date seems arbitrary, as it could just as easily have been set in 1970 or 2015. Vampires and werewolves inhabit this world, but they're limited to a subplot that only tangentially touches on the main plot. There are hints that England was once occupied by Nazis, but nothing is ever made of this. When I read the sequels, I'll be very interested to see if this is groundwork being laid for future plot developments.