Toward the end of last year, Javier Marias was awarded a prestigious Spanish literary prize and the €20,000 that came with it, both of which he had no hesitation in refusing.

His reasons were simple. All his life, he said, he has avoided state institutions and refused to accept any income from the public purse. "I don't want to be seen as an author who is favoured by any particular government."

Noble – and unusual – as Marias's sentiments surely are, he was nevertheless keen to point out that his views applied only to Spanish literary awards. Were the Nobel Committee to call him that would be another matter. And well it might, for Marias must one day be a prime contender if he is not already on the radar.

In his new novel, The Infatuations, the 14th to be translated into English and the first to feature a female narrator, mention is made of the Nobel laureateship. Maria Dolz works in a Madrid publishing house where she is obliged to stroke the egos of authors. One night, after returning from her lover's apartment, she considers how the most unlikely things happen; how, for example, "the school dunce is made a minister and the layabout turns banker". Then, muses Maria, there is the "most simple-minded student" who "becomes a venerated writer and a candidate for the Nobel Prize". This is Marias at his most mischievous, content to have his croissant and eat it.

The first thing to say about The Infatuations is that it is a thriller, but not of the kind that routinely clogs the bestseller lists. On the contrary, it avoids cliche and cardboard characters and is written in a testing style that is reminiscent of Henry James or Virginia Woolf in stream of consciousness mode. Often several pages go by without paragraph breaks and sentences are allowed to run for hundreds of words.

The effect is mesmerising and, on occasion, bewildering. This is not a book to speed read. It was Raymond Chandler who said that "when in doubt, have a man come through a door with a gun in his hand". Marias would never stoop to such unsubtle attention-grabbing. He works by stealth and an accumulation of detail, clarity emerging slowly and circuitously. There is nothing linear about a Marias novel and The Infatuations is no exception.

It begins as Marias means it to go on: "The last time I saw Miguel Desvern or Deverne was also the last time that his wife, Luisa, saw him, which seemed strange, perhaps unfair, given that she was his wife, while I, on the other hand, was a person he had never met, a woman with whom he had never exchanged so much as a single word."

No-one in a creative writing class teaches students to open a novel in this manner. Immediately, though, questions clamour to be answered. Every morning, it transpires, Maria visits a restaurant for breakfast where she observes Luisa and Miguel, a seemingly happy, well-to-do couple with two young children.

She is fascinated by them, possibly more than that. Her interest seems to go beyond curiosity and veers toward stalking. "The nicest thing about them," she writes, "was seeing how much they enjoyed each other's company."

Of course, in novels idylls are simply harbingers of disaster and it strikes soon enough when Miguel – dimple-chinned like Robert Mitchum or Kirk Douglas – is brutally murdered in broad daylight, apparently in a random act by one Madrid's many unemployed.

Now Luisa is a widow and is befriended by Maria, whom she and Miguel had nicknamed the "Prudent Young Woman". Over several glasses of wine Luisa wallows in grief and tries to figure out how to tell her children what has happened. With such an abrupt death there is so much unfinished business, so many loose ends, such a feeling of incompletion, of raggedness and emptiness.

Nevertheless, Maria suggests that Luisa will eventually get over her loss and remarry. Heading the list of suitors is a man called Diaz-Varela, with whom Maria is soon having an affair. But though she is in love with him, he refers to her as his "bird" and behaves in a manner that suggests any infatuation is not reciprocated. Could it be because Diaz-Varela has designs on Luisa? If so, did he conspire to have her husband killed in order to possess her?

As in his previous work, Marias is adroit in evoking tension. His prose is chillingly clear and hypnotically eerie. Like a film director who is content to allow the camera to linger on an actor's face, registering every blink and tic and sniff, he lets his characters talk and talk, as if they were addressing a psychiatrist or a mirror. But at this very fine and disturbing novel's core is a compelling meditation on love in all its ramifications.

The Infatuations

Javier Marias

Hamish Hamilton, £18.99