LONDON — The shortlist for this year’s Man Booker Prize, one of the world’s most prestigious literary awards, includes for the first time a novel told in verse.

The book, “The Long Take,” by the poet Robin Robertson, mixes verse, prose and photographs to follow the story of a World War II veteran across the United States in the golden era of Hollywood. One of the judges, the feminist critic and writer Jacqueline Rose, described it as “a genre-defying novel” that “offers a wholly unique literary voice and form.”

The judges said they realized that its inclusion on the shortlist was likely to set off a debate, but they said its style had not come up in their discussions. Val McDermid, a crime writer, praised its characters, language and the insight it gave into the world. “I’m not sure what else a novel is meant to do,” she said.

Kwame Anthony Appiah, the chairman of the judges, said the six-book shortlist was most notable for the bleakness of its subjects, among them ecological destruction, prison life, institutional racism and slavery.