One of Our Thursdays Is Missing: Jasper Fforde

It is a time of unrest in the Book World. Only the diplomatic skills of ace literary detective Thursday Next can avert a devastating genre war. But a week before the peace talks, Thursday vanishes. Has she simply returned home to the Real World or is this something more sinister? All is not yet lost. Living at the quiet end of speculative fiction is the written Thursday Next, eager to prove herself worthy of her illustrious namesake.
The fictional Thursday is soon hot on the trail of her factual alter-ego, and quickly stumbles upon a plot so fiendish that it threatens the very Book World itself.