Ian McEwan is a dualist: he divides the world into conflicting opposites and makes fiction from the sparks thrown up by their collision. His work thrives on dichotomies and dilemmas: the clash between science and unreason, between rationalism and belief, between public and private. He creates dramas out of accidental occurrences: the disappearance of a young child from a supermarket (The Child in Time , 1987); a ballooning accident in Oxfordshire (Enduring Love , 1998); the sudden appearance of menacing hounds (Black Dogs , 1992).

For McEwan life is a kind of disaster area where random events destabilise even the most ordered existences. In Amsterdam , his sly and absorbing novella, the drama pivots on the discovery of lurid photographs of a right-wing foreign secretary dressed up as a woman. The editor of a struggling broadsheet newspaper buys the photographs of the foreign secretary, an old friend whom he privately despises. Publication, he reasons, will have a dual effect: increase circulation of his newspaper and ruin the politician.

The editor’s actions are denounced by another friend, a self-savouring composer called Clive Linley, who himself is morally compromised when he witnesses the attack of a woman in the Lake District but, comically absorbed by his own “inner-music”, fails to intervene. So we have the ethical conflict - one situation echoing and informing the other - on which the fiction turns.

Amsterdam , like Enduring Love , is written against the template of a thriller; and like all McEwan’s work it has a superb readability. It is also very funny, the final macabre scene, which takes place in Amsterdam, especially so. If there is a weakness it lies in an over-determined, schematic structure - perhaps inevitable in such a short, driven work. Why, for instance, must Linley witness a rape as soon as he visits the Lakes? The event does not emerge organically but seems entirely a function of plot: once Linley leaves London you expect something sinister to happen and sure enough it does. I have walked in the Lakes on countless occasions, yet the most frightening thing I have ever seen was the reflection of my own orange kagoule in a fast-moving stream.

Still, McEwan writes well about newspaper offices (unlike, say, Julian Barnes whose new novel, England, England , full of worthless hacks, seldom rises above heavy-handed caricature). He understands how the proprietorial pressure to impress not just readers but also your peers - by being, in short, first with interviews and stories - compromises and demeans editors, forcing them into morally duplicitous situations. He writes, too, with acute psychological insight about adult friendship, about how so many of us are, like Clive Linley, no more than monoliths of motive: absorbed in our own petty quests for self-fulfilment, quests which can render old friendships as dust.

Ian McEwan is a miniaturist: he shrinks where others enlarge. His work is at its best when at its shortest, when his imaginative brio is most tightly concentrated. His first collection of stories, First Love, Last Rites (1975), had a gruesome originality: experimental work about murder, molestation and incest, stories about lonely sadists, paedophiles and castration. Re-reading these stories you are struck not so much by the content as by the authenticity of the narrative voice. From the start McEwan had his own voice, his own a skewed signature. His mature work may lack the urgency and verbal exuberance of First Love, Last Rites , but his voice and plain, staccato style remain absolutely characteristic. And he still retains a capacity for aesthetic surprise. It is hard to think of a more impressive opening to a novel than the first chapter of Enduring Love , where the chance meeting of two men at the scene of an accident prefigures disasters.

What impresses, in the end, is McEwan’s willingness to grapple with modernity. There is very little about the modern world that does not interest him, from science to politics to musicology. Yet the demand of writing about the way we live today is freighted with difficulty, perhaps because we are so conscious of the world around us changing. No sooner have we attempted to represent our contemporary experience than the picture has altered.

Yet McEwan, almost alone among modern British writers, continues to dissect contemporary morality with the ruthlessness of a child pulling the wings off a butterfly. He knows exactly what he wants to say and how to say it. There are not many writers of whom that is true.