If any few pages of Sally Rooney’s fourth novel blew through the streets on an autumn wind, many a chance reader would be sure who wrote them. They’d recognise the sentences precision-engineered for weight distribution like wide-span bridges. They’d find moment-by-moment emotion, coolly itemised; monosyllabic dialogue occasionally breaking the surface while immense currents of introspection flow beneath; breathtakingly intimate and properly sexy sex, felt from the inside and piously revered as a moral force. Here again, in short order and at great length, are qualities familiar from Conversations with Friends (2017), Normal People (2018) and Beautiful World, Where Are You (2021). Intermezzo is an accomplished continuation of the writing that made Rooney a global phenomenon. It’s also more philosophically ambitious, stylistically varied, disturbing at times and altogether stranger. Two brothers have just lost their father; we’re in the weeks of disorientation after the funeral. Ivan Koubek is 22, quietly cerebral, excelling as a competitive chess player and acutely aware of finding social interaction difficult. He’s “a complete oddball” according to Peter, but then Peter, a smooth-talking barrister who needs to be right, is getting a lot of things wrong. In steadily alternating chapters that carry on, left, right, while the protagonists lose and find their bearings, Ivan embarks on an ardent relationship that surprises all who know him, and sexually voracious Peter, 10 years older, negotiates his desire for two diametrically different women. Ivan’s neurodiverse experience of the world, slowly and attentively rendered, yields its own forms of eloquence, his uncertain use of language contrasting with Peter’s outward fluency, his silences busy with feeling, his mind and body alive with doubt and perception. As suppressed emotions veer sideways, we find Ivan in astonished rapture, and Peter’s self‑satisfaction running close to nihilistic despair. Intermezzo is more philosophically ambitious, stylistically varied, and altogether stranger than Rooney"s previous work Each of Rooney’s novels has choreographed its protagonists in changing configurations, the rhythm of attention turning through interlocking pairs. After the four-square patterning of Conversations with Friends and Beautiful World, and the halting duet of Marianne and Connell in Normal People, we have a sequence for five main characters: two men turning to the three women they need (and a very chic whippet named Alexei). With almost mathematical rigour, symmetries draw our attention to the reversal of roles and doubled traits. Rooney’s art keeps its classic counsel in this way, its control lending gravitas to all that is raw, muddled, mistaken. Age matters, or rather, everyone is trying to work out how it matters. Peter’s generation – the thirtysomethings – are the autumnal elders of this novel, measuring their distance from youth. (As for life past 40, it’s an abstract concept on the margins.) Both brothers are in relation­ships with an age gap. Who is exploiting whom in a romance between people of 22 and 36? Is it “desperately embarrassing”, or might youth and age respectfully, even sublimely, complete each other? Catholic-minded Peter reminds us of Christ’s age at death: 33, the high meridian of life. But how should he love in his prime? There’s a kind of chess move known as an intermezzo. It involves a departure from the obvious course with an unexpected step that requires from the opponent an immediate response. The novel’s lovers and brothers make plenty of moves by which they throw each other off course, often with a logic they can’t acknowledge. They are wrongfooted by death, illness and hurt. But the title becomes meaningful in ways both simpler and larger than this analogy. What if we understand life’s off-kilter interludes as the main action? The whole middle span of life might be made of such intermezzi, inviting us to respond to the moment, improvising. It’s the middle of the chess game that Ivan loves to play. The beginnings are all learned from books of “opening theory”, he explains, and the endings follow certain formulae. It’s in the middle that you create something of your own. Increasingly confident about the love he has found, Ivan honours the discoveries of these few unmoored and shaken months. If bereavement has in some way licensed his new relationship, his ecstatic fulfilment with Margaret also allows him to grieve. Sensible, yearning Margaret, who runs an arts centre in rural Leitrim, sees the reciprocity of living and mourning, urging that the only answer to death is to “echo back its name … with all the same intensity and senselessness, on the side of life”. In something like an epiphany at the novel’s mid-point, the habitual currency of doubt, silence and sublimation falls away and Ivan feels the depth of his loss. It’s one of the novel’s remarkable sequences of thought, sequences that build to cumulonimbus heights, growing behind the inadequate or misfiring conversations, or rising freely, with a sort of grandeur, from the nonverbal core of sexual pleasure. Peter grapples more messily with Eros, Thanatos and much in between. He swings between thoughts of suicide (cue inner identification with Hamlet), desire for young, glowing, usually naked Naomi, and desire for Sylvia, the brilliant academic who was his lover before an accident left her in chronic pain. Sylvia is still charismatically alive, and Peter still deeply attracted to her, but he thinks grimly of their relationship as “mutilated by circumstance into something illegible”. The end of her sexual life is cast, in some of the novel’s most troubling passages, as tantamount to death. We find little counter to the notion that Sylvia is a broken sex provider who cannot offer him fulfilment. “Talk to someone he would nearly like to.” “Better for both of them if he. Yes. No.” That’s Peter vacillating. The style recalls, unmistakably, Joyce’s rendering of Leopold Bloom as he goes pondering, loving and sorrowing his way through the Dublin streets of Ulysses. As Peter lurches through his crisis, swigging vodka from a lemonade bottle, searching for some familial figure, we seem to be in company with both Bloom and Stephen Dedalus, Joyce’s two male protagonists of contrasting age and disposition, who passed this way a century ago. It’s intriguing to see Rooney, whose inheritance is more obviously from the celebrated “scrupulous meanness” of Dubliners, involving herself so thoroughly with Ulysses. She remains very much her own writer in this relationship, achieving an effect quite different from Joyce, whose commodious notation of Bloom’s roaming thoughts spins outward across languages, places, incongruous rhymes, his every line proposing games of association. Rooney’s elliptical phrases show us perceptions bent uncomfortably out of shape. And all the while she honours her subjects with intent seriousness rather than with play. Tightening her focus on the immediate, she exerts a centripetal pressure. My instinct while reading is to throw open a window, look at a painting, anything to allay the claustrophobia induced by being kept so close to people absorbed exclusively by their feelings, right now this moment, for each other. But art does its job when it pulls us beyond our instincts to experience other ways of being. Intermezzo is itself about life as continuous experiment. The novel suggests that Rooney (at Peter’s age, 33) won’t be settling in the shapes she has established, but holding us, with mixed joy and unease, in strenuous irresolution. Intermezzo by Sally Rooney is published by Faber (£20). To support the Guardian and the Observer, order your copy at guardianbookshop.com. Delivery charges may apply.