The Eyre Affair by Jasper Fforde (2002)

The story takes place in an alternate 1985, where Thursday Next, intrepid Special Operative battles an arch-villain who's kidnapping characters from classic literature. As a member of the Literary Detective Division of the Special Operations Network, she pursues literary crimes such as forgery, plagiarism, manuscript theft, and the abuse of literary characters.

In Japser Fforde’s world, matters of literature receive the kind attention we reserve for professional sports or Hollywood celebrities. The novel is fun and diverting with a great arch-villain and an intrepid heroine.

Full of literary allusions, this is a good novel for readers of classic fiction. People are able to pop themselves into novels, while fictional creations are able to escape into the real world. There is also a funny bit where a production of Richard III is done with boisterous audience participation à la The Rocky Horror Picture Show.
The Eyre Affair is the first of seven in the Thursday Next series (the next is Lost in a Good Book).