Alternate reality, time travel, literary references, quirky characters, science fiction, romance, and crime thriller ... if any of these appeal to you, you might just love The Eyre Affair by Jasper Fforde.
Thursday Next is a Special Ops cop in an alternative reality England circa 1985. She investigates literary crimes and someone has just perpetrated a couple of doozies by stealing an original Dickens manuscript and kidnapping Jane Eyre from the original Bronte work. Thursday deals with corruption, politics, co-workers, and bad guys as she tries to rescue Jane, deal with demons from her past, and reconnect with the love of her life. Funny and quirky, with lots of historical and literary references to keep you guessing.
First in a series. If you like The Eyre Affair follow it up with:
Lost in a Good Book
The Well of Lost Plots
First Among Sequels
One of Our Thursdays is Missing
The Woman Who Died A Lot
or try Fforde's Nursey Crime series:
The Big Over Easy
The Fourth Bear