The Parts by Keith Ridgway

Keith Ridgway's first novel, The Long Falling (1998), announced a considerable new talent. Acclaimed on both sides of the Atlantic, the book was also a particular success in France, winning two major awards. An accomplished collection of stories – Standard Time – followed, which won the 2001 Rooney Prize. With The Parts, his fictional landscape moves to present-day Dublin. Ridgway aims to capture the variety of the new, Europeanised city in the form of the baggy, multiple-plotted "doorstop novel" so beloved in America.

Six characters vie for space, their perspectives introduced throughout by a designating symbol. Millionairess Delly Roche (symbol: a house) "needed to die like other people needed to eat". As she endlessly slips away, her companion Kitty Flood (symbol: a knife and fork) is preoccupied by surfing teen chat-rooms under eight aliases, gleaning verisimilitude for a novel. Meanwhile, Roche's adopted son, Dr George (symbol: a car) alternates between overseeing her care and engaging in the secret research on which the storyline rests.

The most vibrant – and funniest – passages concern the accidental sleuths Joe Kavanagh, a radio host (symbol: a radio), and his show's gay producer, Barry (symbol: a man). Kavanagh reveals his own moral exhaustion in the desperate search for an ever more sensational roster of guests. Barry's character allows for the evocative description of a narrow, metropolitan gay scene – and a subplot straight out of 19th-century naturalism. Dispatched to persuade a rent boy to appear on the programme, Barry promptly falls in love with "Kez" (symbol: a mobile phone), aka "something heartbreaking in a Diesel T-shirt and cargo pants".

Ridgway's control of material is confident, and the sudden displacement of one storyline by Kez's own, which interrupts like a mobile phone call, is innovative. But the ever-expanding canvas of The Parts allows the necessary psychological tension of what is, essentially, a thriller plot to dissipate. We become involved in someone's desperation or confinement, only – too swiftly – to be released from it.

There's an occasional verboseness, too, as the narrative struggles to accommodate a shaggy-dog-tale inclusiveness. The use of symbols to indicate viewpoint is admittedly only an editorial fault. But it makes The Parts look dumber than it is, and suggests a lack of faith in Ridgway's rather accomplished presentation of six sensibilities.

To coincide with The Parts, Faber has issued Ridgway's breakthrough novella Horses (£4.99; first published in a 1997 anthology) as a discrete book. This beautifully taut tale conjures up the elemental, rural Ireland that, understandably, still haunts much of the country's sensibility and literature. A million miles from the material high-jinks of The Parts, Horses – for all its brevity – packs the weightier punch.

That's because (as Dr George recognises on finding a guy pimping for his own brother) for all its cosmopolitanism, Dublin can still feel so small that it resembles "being at a private party". In Joyce's epic of the city on the Liffey, Stephen Dedalus famously argued that History "is a nightmare from which I am trying to awake". The structural cohesion of Ulysses, however, rested on this uncomfortable sense of a coercive, singular culture or history permeating even the lives of the outsiders Dedalus and Leopold Bloom.

Ridgway's city, meanwhile, appears confidently to explode, proliferate, to contain multitudes. Yet, though distinct pasts and secrets dictate to each character, the book's storyline perversely demands a somewhat underwhelming, parlour game-like resolution. Ridgway remains a writer to watch. The Parts, however, ultimately amounts to something less than its whole.

Richard Canning, author of 'Gay Fiction Speaks', is writing a biography of Ronald Firbank