U.S. writer A.M. Homes denies Hilary Mantel literary treble By Paul Casciato LONDON (Reuters) - The American novelist A.M. Homes beat double Man Booker Prize-winner Hilary Mantel to the 2013 Women's Prize for Fiction on Wednesday with a tale of murder, sibling rivalry, adultery and absolution. Homes's "May We Be Forgiven," which follows a violent change in the lives of a historian and his high-flying younger brother, secured the 30,000 pound ($45,900) award for Homes despite bookmakers heavily favoring a triple sweep for Mantel's bestselling "Bring Up the Bodies," already winner of the Booker and Costa awards. Homes told Reuters that the prize was an enormous affirmation for a woman writer whose narratives are often written from the male perspective, and who feels she falls in a gap between male and female writers. "To be given this award in particular is an incredible vote of confidence in the range of writing that women do and in the seriousness of that writing," she said. The chair of the judges, Miranda Richardson, said the panel argued long and passionately over a shortlist that also included former winners Briton Zadie Smith and U.S. novelist Barbara Kingsolver, as well as U.S. screenwriter-turned-novelist Maria Semple and British writer Kate Atkinson. "But in the end we agreed that 'May We Be Forgiven' is a dazzling, original, viscerally funny black comedy - a subversion of the American dream," she said. The darkly comic story follows the historian Harold Silver, who has spent a lifetime watching his taller, smarter and more successful younger brother George acquire a covetable wife, two children and a beautiful home in New York. But George has a murderous temper and when he loses control the two brothers are hurled into entirely new lives in which they must both seek absolution. Homes, whose first name is Amy, often laces her novels with violence, sex and black humor. The author of "This Book Will Save Your Life" and "The End of Alice" said her writing explored the American dream turned on its head, upside down or inside out. "I sometimes describe it as a kind of emotional science fiction," she said. That it takes the edges of reality and pushes it ever so slightly further out. The British bookseller Foyles said "May We Be Forgiven" was a "crowning achievement" for Homes that put her among contemporary American greats such as Pulitzer prize-winner Cormac McCarthy and "Independence Day" author Richard Ford. "It's a powerful exploration of where the American dream went wrong, laced with sharp observation, pathos and dark humor," Foyles said in a statement. British bookmakers William Hill had made Mantel odds-on favorite to win the prize with her 11th novel, her third appearance on the Women's Prize shortlist. Homes and Zadie Smith's "NW" were joint second. Mantel won the Booker in 2009 for "Wolf Hall" and in 2012 for "Bring Up the Bodies," the first two books in a trilogy about the rise and fall of the 'eminence grise' Thomas Cromwell in the court of King Henry VIII. She won the 2012 Costa Book Award in January. Mantel, who expects to finish the third book in her trilogy in the next 18 months to two years, praised the high quality of the other authors on the shortlist for this year's prize. She said she was very pleased for Homes and remained philosophical about losing her third nomination. "It's the one that's proving elusive for me," she told Reuters. But I've got plenty of books to come. Plenty of other chances, I hope. The Women's Prize for Fiction, previously known as the Orange Prize for Fiction, was set up in 1996 to promote fiction written by women. It is awarded to the best novel of the year written in English by a woman. Homes joins a celebrated list of previous winners, including Madeline Miller for "The Song of Achilles" in 2012, Téa Obreht for "The Tiger's Wife" (2011) and Lionel Shriver for "We Need to Talk About Kevin" (2005). $1 = 0.6539 British pounds Reporting by Paul Casciato; Editing by Kevin Liffey