Early in his second novel, The Comfort of Strangers (1981), Ian McEwan calls up Mozart to usher in the theme which virtually dominates all his work. Colin, who is on holiday with Mary, hears a man singing in the shower: “tra-la-ing the forgotten words, bellowing out the orchestral parts, ‘Mann und Weib, Und Weib und Mann, together make a godly span.’” If one were to produce a template for the McEwan novel, its three essential features would be a relationship between a man and a woman, an external threat which clarifies the nature of that relationship, and a prose style equal to that of any writer in English today. The template would not fit McEwan's one book for children, The Daydreamer (1994), but it would serve for all his novels, from the first, The Cement Garden (1978)—the couple there is an incestuous brother and sister—to his latest. Its title, Enduring Love, explicitly announces McEwan's perennial romantic theme, but the effortful pun—love that lasts may also have to be suffered—reminds us that, although some of his couples may live to enjoy “a godly span”, all of them go through hell.

Joe and Clarissa are a happy couple. He is a science journalist and she is an academic. McEwan's first two novels seemed to issue direct from an imagination complete in itself, diamond-hard, exact and exacting. His third, The Child in Time (1987), mentions three non-fiction books on its acknowledgements page; storytelling has broadened out into an engagement with political and cultural forces. Enduring Love acknowledges ten books and also includes a list of twenty medical papers. One has a sense of fiction threatened by background reading, of the novelist's bookcase toppling on top of him. As if to counteract the danger of the book's being hobbled by its themes, there are thriller-like injections of action: a high-speed drive, two shootings, a hostage. These follow on from the book's central triangle; Joe and Clarissa may be in love, but someone else is obsessed with Joe. He has a stalker or, as his researches tell him, he is being pursued by someone with “de Clérambault's syndrome”.

A significant moment in The Comfort of Strangers has a woman asking Mary about her relationship with Colin: “Are you in love?” It seems an innocuous question, until the woman reveals what it means to her: “If you are in love with someone, you would even be prepared to let them kill you, if necessary.” Jed Parry, the man obsessed with Joe, is another example of an extreme manifestation of love, and one which is meant to throw light on what it means for people like Joe and Clarissa to be in love, but not pathologically so. There is something rather predetermined in McEwan's use of de Clérambault's syndrome as a kind of rabid stalking-horse, behind which he can approach more ordinary forms of love. Jed's continual presence under Joe's window and his repeated phone calls and letters lead to a breakdown of trust between Joe and Clarissa. For the science journalist, reconciliation is a matter of checking references and collating information. The way to regain his lover is to understand Jed: “For there to be a pathology there had to be a lurking concept of health. … Sickness and health. In other words, what could I learn about Parry that would restore me to Clarissa?” The novel has two appendices. The second is another letter from Jed, unrepentant and ecstatic to the end; the first rounds up the medical background, finishing with a quotation from the British Journal of Psychiatry: “the pathological extensions of love not only touch upon but overlap with normal experience, and it is not always easy to accept that one of our most valued experiences may merge into psychopathology.”

Joe and Jed are brought together by chance when they are caught up in a ballooning accident, the superb scene with which the novel begins. McEwan is a master of accidents and the procedures of mayhem, the stretching of time that occurs as brain and body are doused in shock (the car crash in The Child in Time or the killing of a man and his dismemberment—partly for love—in The Innocent). He specializes in graphic stillness, in a charged attention to the immediate detail which prefigures a larger emotional or psychological truth. In The Cement Garden there is a moment when the brother and sister “looked at each other knowingly, knowing nothing”, and this is emblematic of the disturbing ambivalences of McEwan's style, of its ability to be both scrupulously neutral and pulsing with psychological energy. In Enduring Love, the balloon accident causes a man's death, and when Joe visits the man's widow, an academic living in North Oxford, she is created for the reader by a description of her home:

No colours but brown and cream. No design or style, no comfort, and in winter, very little warmth. Even the light was brownish, at one with the smells of damp, coal dust and soap. … There was lino, and grimy electrical piping on the walls, and from the kitchen, the sour scent of gas, and a glimpse of laminated shelves on metal brackets supporting bottles of brown and red sauce. This was the austerity once thought appropriate to the intellectual life, unsensually aligned to the soul of English pragmatism, unfussy, honed to the essential, to the collegiate world beyond the shops. In its time it might have appeared to strike a blow at the Edwardian encumbrances of a older generation. Now it seemed a perfect setting for sorrow.

Is it significant that one of the best passages in the book should be devoted to a secondary character?

Enduring Love is narrated by Joe, who describes himself as “a large, clumsy, balding fellow”. Extending this clumsiness to some of the novel's methods may be a gain in verisimilitude (name three great novels by science journalists), but the book suffers too much as a result. Joe is determined to understand things—the accident, his relationship with Clarissa, Jed's obsession with him—and, as a result, the narrative is constantly diverted by his need to analyse. The opening sentence is one of a number that proclaims a self-aware narrative, a story as experiment, one where the telling will distance us from what is told: “The beginning is simple to mark.” More disabling, though, than this verbal tic (“I see us from three hundred feet up … I'm holding back the information … let me freeze the frame. …”) is the way Jed and Clarissa are not really granted their own inner lives. Rather awkwardly, Chapter Nine is told from Clarissa's point of view, because, as Joe tells us, “It would make more sense.” Soon, however, he is back to seeing her from outside and at risk of reducing her to little more than a mood and an eye-colour: “She drew her breath sharply and shot me a beam of angry green.”

Jed's obsession with Joe is intensified by religious mania. The instructions on his answering machine give some measure of the man: “Please leave your message after the tone. And may the Lord be with you.” There is a fractured comedy in his first approaches to Joe and in Joe's baffled response, the funnier for the absence of any cues to suggest that the scene is meant to be funny. (Conversely, when Joe buys a gun from some hippies, McEwan's busy signalling of the scene's hilarity—one hippy has a comic moustache which gives Joe the giggles—is rather desperate.) We learn most about Jed from his letters to Joe. However, the epistolary mode is rarely as engaging as dialogue or soliloquy, and Jed can seem as much a function of the novel's thriller-like conventions (the Threat) as a fully realized character. McEwan may have set out to invoke certain genres by having two chapters end with threatening phone calls or by naming a virtuous character Bonny Deedes, but Enduring Love lacks the singleness of narrative vision required by these sorts of model. The divagations into scientific theory and the mysteries of love, although they have an intellectual reach fitting for the literary novel, occur too obtrusively for theme and story to have a complementary wholeness (as in The Child in Time). Ian McEwan's career is testament to his readiness to extend his immense gifts by dealing with an ever-larger range of subjects. Enduring Love opens with an over-buoyant balloon carried off by the wind; the novel's problems are of an opposite kind: too much ballast.