While this year's shortlist has been the best-selling in Booker history, some in the literary world have accused the prize of becoming too populist.
The other nominees are Carol Birch, Patrick deWitt, Esi Edugyan, Stephen Kelman and AD Miller.
The £50,000 prize winner will be announced at London's Guildhall.
Bookmakers William Hill and Ladbrokes both have Barnes to win, with Birch's Jamrach's Menagerie as second favourite.
"We are bracing ourselves for a Booker battering as literary punters seem to believe Barnes is a banker bet," said Hill's spokesman Graham Sharpe.
Previous years have shown, however, that the Booker winner is notoriously hard to predict.
Last year Tom McCarthy's C had been the favourite to win, but the prize went to Howard Jacobson for his comic novel The Finkler Question.
MAN BOOKER 2011 SHORTLIST
- Julian Barnes - The Sense of an Ending
- Carol Birch - Jamrach's Menagerie
- Patrick deWitt - The Sisters Brothers
- Esi Edugyan - Half Blood Blues
- Stephen Kelman - Pigeon English
- AD Miller - Snowdrops
But critics have accused the Booker judges of dumbing down, and one group of literary leading lights announced a rival award, The Literature Prize.
The award's backers claimed the Booker "now prioritises a notion of 'readability' over artistic achievement".
Ion Trewin, the Booker's literary director, dismissed the announcement as "a minor distraction".
"Do I detect sour grapes in some of those who support the possibility of a new literary prize, said to be a rival to the Man Booker?" he wrote in the Telegraph on Monday.
But this year's judges faced more criticism from Sir Andrew Motion, who chaired the Booker panel in 2010.
The former poet laureate told The Guardian the focus on readability "opens up a completely false divide between what is high end and what is readable, as if they are somehow in opposition to one other, which is patently not true".
Earlier in October, the New Statesman's lead fiction reviewer Leo Robson wrote: "If things continue as they are, it isn't hard to imagine a time when the prize will be seen as a way not of celebrating novels, just of selling them."
William Hill said more than 50% of all bets on the Man Booker Prize had been for Julian Barnes, who has been shortlisted for the prize on three previous occasions, but without success.
The 65-year-old was nominated in 1984 for Flaubert's Parrot, in 1998 for England, England and in 2005 for Arthur and George.
Rest at BBC News.