Marisa is cool to the point of severity, thoroughbred, well-educated, fiercely unmaternal and mildly under-occupied. While Felix deals in antiquarian books, Marisa divides her time between altruism and narcissism – working as a volunteer for an Oxfam bookshop and the Samaritans, reading aloud to a blind man (Felix fantasises that she does so naked), visiting the manicurist and acting as a guide at the Wallace Collection, that jewel box of assorted artistic ravishments improbably hidden off the garish thoroughfare of Oxford Street. She is, her husband tells us, unable to recognise herself in these activities. She only feels truly herself when ­dancing.

It is the Wallace Collection that provides the setting for Marisa’s seduction by (and of) her lover Marius, “a character in a salacious fiction I wrote,” (writes Felix) “in imitation of all the salacious fiction I’d ever read”. He is, indeed, a figure straight from the pages of Sacher-Masoch: opal-eyed, walrus moustached, dyspeptic, oblique, Satanic. Felix takes to describing the trio formed by Marisa, Marius and himself as “our little family”. One does not expect a cheerful ending to this sort of drama, nor is there one. After an elaborately staged dance scene in a park, at which Marisa may or may not feel, for a terpsichorean instant, truly herself, a tragic conclusion is inevitable.

The ending of Jacobson’s remarkable novel, which conforms to the conventions of the pornographic imagination by dispensing summarily with a character for whom no imaginative purpose remains, is the weakest point of a book that, until that point, is as interested in the perturbations of the human soul as in carnality. “I was a Frenchman, not an American, in my erotic life, seeking carnality’s greatest prize – extinction”, Felix asserts, explicitly aligning The Act of Love (presumably for the benefit of readers who hadn’t already twigged) with the great European tradition of ­philosophico-­erotic ­fiction.

Not that anyone could mistake it for anything else. The torrent of ideas, the urgent energy of their expression, the erotic tension between that and the extreme, mannered, elegant restraint of the plotting, the charm and intense, preposterous, virtuoso prettiness in which the perversity is decked, all place The Act of Love firmly in the canon that encompasses the Marquis de Sade, Pauline Réage and Georges Bataille, but also Nabokov and Henry James. It is certainly the most interesting, complicated and troubling novel of Jacobson’s career to date.