Irish writer Sebastian Barry is the bookmakers' favourite to win the Man Booker Prize for The Secret Scripture.
The author is ahead of shortlisted rivals Steve Toltz, Linda Grant and Amitav Ghosh.
Indian-born first-time novelist Aravind Adiga, who at 33 is the youngest writer on the list, is trailing the field with odds of 7/1.
The winning writer will be handed a cheque for £50,000 at a ceremony in London this evening.
The triumphant author can also expect an upturn in sales and added recognition.
Barry's novel A Long Long Way was shortlisted for the Booker Prize in 2005.
BOOKER PRIZE - ODDS
The Secret Scripture Sebastian Barry - 7/4
A Fraction of The Whole Steve Toltz - 9/2
The Clothes on Their Backs Linda Grant - 9/2
Sea of Poppies Amitav Ghosh - 9/2
The Northern Clemency Philip Hensher - 5/1
The White Tiger Aravind Adiga - 7/1
Source: William Hill
Grant and Philip Hensher were also nominated for the prize in 2002, but failed to win.
Michael Portillo, the Booker chair of judges, called the six final works "intensely readable", adding they are "extraordinary examples of imagination and narrative".
"These books are, in every case, both ambitious and approachable," he added.
For the first time, extracts of each shortlisted novels will be available to download onto mobiles.
Dublin-born Barry has written a number of plays and novels, winning a number of prizes.
The Secret Scripture, told through the journals of Roseanne McNulty and her psychiatrist, is the story of a life blighted by mistreatment - and yet still marked by love and hope - in 1930s Sligo.
Through the haze of memory, Roseanne's story acts as an alternative, secret history of Ireland.