The decision to award this year’s Man Booker Prize to the virtually unknown 28-year-old New Zealand writer Eleanor Catton for her door-stopper of a novel, The Luminaries, is as much a recognition of a new voice as proof that the Booker judges’ capacity to surprise remains undiminished. In a year when the critics and bookies were rooting for one of the shortest novels in contention — the British writer Jim Grace’s Harvest — they went and chose the longest (The Luminaries clocks in at 832 pages) and the most formally structured contender. Yet in the past they have gone for novels that were so brief (Ian McEwan’s Amsterdam and Julian Barnes’s The Sense of an Ending) that many questioned whether they could be considered as novels at all. Two years ago, there was a huge row when one of the judges suggested that for him a book needed to “zip along” to pass the selection test, prompting criticism that the prize had dumbed down with “readability” taking precedence over “artistic achievement.” This year’s choice is a riposte to critics on both counts. Good literature transcends considerations of structure and size. Robert Macfarlane, chairman of the judges, described The Luminaries as a “dazzling book, vast without being sprawling.” Hailed as a “compelling’’ thriller, it is set against the background of the 19th century New Zealand gold rush. The story is told through a complicated plot structure divided into 12 zodiac-themed chapters, each decreasing in length in conjunction with the lunar cycle. Judges acknowledged that readers needed to make a “huge investment” in getting to grips with it, but the effort was worth it.

At 28, Catton is the youngest ever writer to win the Booker, beating Ben Okri, who was 32 when he won it for The Famished Road in 1991. It is after 28 years that a New Zealander has won the prize since Keri Hulme got it for The Bone People in 1985. That was a controversial choice, still cited after so many years as an example of the Booker’s “eccentric’’ ways. Perhaps no other literary prize is scrutinised as closely as Booker amid persistent rumours about its imminent death. Consistently, however, it has always proved its critics wrong, demonstrating that even after 45 years, there is still life left in the old beast. In India, there will be disappointment that Jhumpa Lahiri’s The Lowland missed out and elsewhere too, critics will carp that their favourite was ignored. But that’s the beauty of Booker — its unpredictability. From next year, the prize will be open to American and other writers with British publishers, making the competition tougher — and adding to the drama that has become so much a part of one of the English-speaking world’s most storied prizes for writing.

In an earlier version of this editorial, Ian McEwan's Booker Prize winning novel was incorrectly identified as Chesil Beach

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