The End of Mr. Y, by Scarlett Thomas

At a point when quick profits and publicity angles are paramount to publishers, it's reassuring to see Scarlett Thomas forge a career that has matured at a gentle pace and without diluting her idiosyncratic style. Over the past decade her work has progressed from whimsical crime fiction to zeitgeist-surfing drama. Her latest, The End of Mr. Y, could prove to be her masterpiece. I don't know any other book that has made me, or anyone, simultaneously ponder the mating logistics of rodents, turn-of-the-century homeopathy and the consequences of time travel.

Ariel Manto is a typical Thomas creation: feisty, intelligent and highly sexed. A PhD student at a sleepy university (Thomas teaches English Literature and Creative Writing at the University of Kent), Ariel is semi-content to bumble along, flitting between her studies and a sordid affair with an older, married professor. Her life is simultaneously prosaic and peculiar; she has a mildew-ridden flat, her finances are poor, her lover likes bondage and her college supervisor has vanished. "Real life is regularly running out of money, and then food," acknowledges Ariel, "Real life is physical. Give me books instead: give me the invisibility of the contents of books, the thoughts, the ideas, the images."

Ariel's thesis is on 19th-century thought experiments but her obsession is the work of Thomas Lumas, an obscure Victorian novelist. His final, extremely rare work, The End of Mr. Y, is said to curse all who read it. Finish it and it finishes you. When Ariel finds a copy in a second-hand store she discovers that it holds the key to entering the Troposphere, a gateway into the minds and histories of other people (or animals).

That Ariel will try it out is inevitable, the results are not. What starts as a very English take on The Shadow of the Wind suddenly revs up a gear into the realm of The Matrix. Along the way we are treated to discourses on Derrida's deconstructionism, a theological romance, horny mice and sinister mind police.

In addition to un-spooling a breakneck plot, Thomas takes the reader down a dizzying array of literary, historical and psychological avenues. Extracts from Lumas's opus allow for a pastiche of period prose to rival that of Michel Faber, steeped in the doom-laden atmospherics of Conan-Doyle and Poe. There are also some wonderful reminders of that singularly Victorian infatuation for all things spectral; their need to capture the "ether" the way Pitt-Rivers pinned down the world's beetles and butterflies.

As with her previous novel, PopCo, Thomas shows she is equally savvy with contemporary preoccupations. "I get claustrophobic in big cities," admits Ariel, "overwhelmed by all that desire in one small place, all those people trying to suck things into themselves: sandwiches, cola, sushi, brand labels, goods, goods, goods." Her signature sassy sexiness is summed up in an amusing line of biblio-porn: "I try not to get too absorbed with touching their wide green spines, then opening them and running my fingers over the thick, pulp rag paper that still seems to contain tiny bits of tree."

However, it is in her exploration of relativity and reality that Thomas is really daring. She neatly marries these difficult themes into an engaging story. We're just a molecular iPod shuffle away from being a pigeon or a pin. Ariel's Tropospherical adventures play out like she's a laptop switching to wireless in search of a cerebral account to tap into. It's a funny, thought-provoking setup and makes for a phantasmagorical novel Lumas himself would be proud of.

Canongate £12.99