Shipstead, born in 1983, was one of five shortlisted authors for the award, which comes with a 30,000 pound ($50,000) cheque.

"The winner of the Dylan Thomas Prize before she's 30, the smart money has to be on Maggie Shipstead winning a Pulitzer before she's 50," said novelist Allison Pearson, who was on the judging panel.

"Shipstead has imagined herself inside the head of a 59-year-old male in the grip of an erotic infatuation," she added. "This is territory that has been covered by the greats of American fiction, including John Updike and Jane Smiley.

"Maggie Shipstead doesn't just follow in their footsteps; she beats a distinctive and dazzling path of her own. The world has found a remarkable, humane new voice to explain us to ourselves."

The 59-year-old of the story is Winn, a well-to-do family patriarch who faces a mid-life crisis as the wedding of his eldest daughter Daphne approaches.

Published in May, "Seating Arrangements" won warm praise from U.S. critics including Dylan Landis in the New York Times.

"Frequent shifts in point of view give the book a waltzlike rhythm, with beats of startling beauty," Landis wrote, describing Shipstead's book as "smart and frothy".

Open to any published author in the English language under the age of 30, the award celebrates the legacy of Welsh poet and writer Dylan Thomas who, the prize organisers said, wrote most of his best work in his 20s.

The other Dylan Thomas Prize nominees this year were Tom Benn (The Doll Princess), Andrea Eames (The White Shadow), Chibundu Onuzo (The Spider King's Daughter) and D.W. Wilson (Once You Break A Knuckle).

Previous winners were Rachel Trezise, whose "Fresh Apples" won the inaugural prize in 2006, Vietnamese writer Nam Le with "The Boat" (2008), Elyse Fenton for "Clamour" (2010) and Lucy Caldwell for "The Meeting Point" (2011).

(Reporting by Mike Collett-White; editing by Patricia Reaney)

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