The novel, Reading in the Dark, by Seamus Deane, has won the annual Guardian Fiction Prize.
"It had lyricism, mystery and passion it was superbly controlled, beautifully paced," the judges said. "A gripping tale was told through an incomparably rich and poetic style."
Deane, as winner of the prize, which was established in 1965 to recognise works of fiction showing originality and promise by a "British or Commonwealth" writer, will receive £3,000.