To whom hasn't Jasper Fforde and his cult ''literary detective'' heroine Thursday Next been compared? The blurbs on Fforde's second Next fantasy adventure, Lost in a Good Book (Viking, $24.95), cite everyone from Stephen Hawking to Bridget Jones to Nancy Drew to Monty Python to Buffy the Vampire Slayer. In Fforde's loony otherworld -- in which Fort Knox holds the Library of Congress' most valuable books and bad guys escape via time travel -- Ms. Next is a ''LiteraTec'' gumshoe, a government lackey-turned-celebrity since saving Jane Eyre in 2002's ''The Eyre Affair.'' ''Lost'' is even more richly crammed with jokes, ideas, and action. After her new hubby is erased by an evil corporation, Next book-hops into ''Sense and Sensibility'' with ''Great Expectations''' Miss Havisham, defends herself inside Kafka's ''The Trial,'' and springs a nemesis from the pages of Poe's ''The Raven.'' Brainier silliness is hard to find.