NEW YORK -- Bob Dylan, Nobel laureate. In the book world's equivalent of a Supreme Court ruling, the Nobel judges declared Thursday that Dylan is not just a rock star but a poet of the very highest order.

Dylan, 75, becomes the first musician in the 115-year history of the Nobel to win the prize in literature. He was honoured for "having created new poetic expressions within the great American song tradition."

It is the ultimate ascension for the man who set off a lasting debate over whether lyrics, especially rock lyrics, can be regarded as art. Dylan, who gave the world "Like a Rolling Stone," "Blowin' in the Wind" and dozens of other standards, now finds himself on a list that includes Samuel Beckett, Toni Morrison and T.S. Eliot, whom Dylan referred to in his epic song "Desolation Row."

"Congratulations to one of my favourite poets, Bob Dylan, on a well-deserved Nobel," tweeted President Barack Obama, who in 2012 presented the singer-songwriter with a Presidential Medal of Freedom.

Dylan rarely gives interviews, and a representative said the star had no immediate comment. He performed a 90-minute concert in Las Vegas Thursday night but did not mention the Nobel honour.

The startling announcement out of Stockholm was met with both euphoria and dismay.

Many fans already quote Dylan as if he were Shakespeare, there are entire college courses and scholarly volumes devoted to his songs, and judges work Dylan quotations into their legal opinions all the time, such as "The times they are a-changing" and "You don't need a weatherman to know which way the wind blows."

With this year's Nobel announcement, many people, especially Americans, weren't scratching their heads and asking "Who?!" the way they did after hearing the names of such winners as Patrick Modiano and J.M.G. Le Clezio.

Others, though, lamented a lost moment for books.

"An ill-conceived nostalgia award wrenched from the rancid prostates of senile, gibbering hippies," wrote "Trainspotting" novelist Irvine Welsh. "I totally get the Nobel committee," tweeted author Gary Shteyngart. "Reading books is hard." The Vatican newspaper L'Osservatore Romano said some "real writers" probably aren't pleased.

But several leading authors praised the news.

Nobel laureate Toni Morrison said in a statement that she was pleased and that Dylan was "an impressive choice." Salman Rushdie, who has written songs with U2's Bono, tweeted that Dylan is "the brilliant inheritor of the bardic tradition. Great choice." Perennial Nobel candidate Joyce Carol Oates tweeted that "his haunting music & lyrics have always seemed, in the deepest sense, literary."

Dylan's award also was welcomed by a venerable literary organization, the Academy of American Poets.

"Bob Dylan receiving the Nobel Prize in literature acknowledges the importance of literature's oral tradition, and the fact that literature and poetry exists in culture in multiple modes," executive director Jennifer Benka said in a statement.

Critics can argue whether "Visions of Johanna" is as literary as "Waiting for Godot," but Dylan's stature among musicians is unchallenged. He is the most influential songwriter of his time, who brought a new depth, range and complexity to rock lyrics and freed Bruce Springsteen, Joni Mitchell and countless other artists to break out from the once-narrow boundaries of love and dance songs.

Dylan already was the only rock star to receive a Pulitzer Prize (an honorary one), and is, in fact, an author, too: He was nominated for a National Book Critics Circle prize for his memoir, "Chronicles: Volume One."

He is the first American to win the Nobel literature prize since Morrison in 1993, and his award probably hurts the chances of such older American writers as Philip Roth and Don DeLillo, since the Nobel judges try to spread the honours around.

"Rather doubt Philip Roth and Don DeLillo wish they'd written "Mr. Tambourine Man" vs. AMERICAN PASTORAL and UNDERWORLD," tweeted Roth biographer Blake Bailey, referring to acclaimed novels by Roth and DeLillo. "But sure, ok."

Dylan's life has been a hybrid of popular and literary influences. A native of Duluth, Minnesota, he worshipped Elvis Presley and James Dean as a boy, but also read voraciously and seemed to absorb virtually every style of American music.

His lyrics have referred to (and sometimes lifted from) the Bible, Civil War poetry and Herman Melville. He has contended that his classic "Blood on the Tracks" album was inspired by the stories of Anton Chekhov.

His songs can be snarling and accusatory ("Idiot Wind," "Positively 4th Street"); apocalyptic ("A Hard Rain's A-Gonna Fall"); dense and hallucinatory ("Desolation Row"); tender and wistful ("Visions of Johanna"); bracingly topical ("Hurricane" and "Only a Pawn in Their Game"); and enigmatic and absurdist ("Stuck Inside of Mobile With the Memphis Blues Again").

"Blowin' in the Wind" was an instant protest anthem for the 1960s, yet sounded as if it had been handed down through the oral tradition from another century, with such lines as "How many times must the cannon balls fly before they're forever banned?"

"Like a Rolling Stone," his takedown of a rich and pampered young woman forced to fend for herself, was pronounced the greatest song of all time by Rolling Stone magazine. The six-minute recording from 1965 is regarded as a landmark that shattered the notion a hit song had to be three minutes.

At a 1965 press conference, he was asked whether he considered himself primarily a singer or a poet. Dylan wisecracked: "I think of myself more as a song-and-dance man."

His career has been such a complicated pastiche of elusive, ever-changing styles that it took six actors -- including Cate Blanchett -- to portray him in the 2007 movie based on his life, "I'm Not There." He won an Oscar in 2001 for the song "Things Have Changed" and received a lifetime achievement award from the Academy of Recording Arts and Sciences in 1991.

Dylan is the most unorthodox Nobel literature prize winner since 1997, when the award went to Italian playwright Dario Fo, whose works some say also need to be performed to be fully appreciated. By a sad coincidence, Fo died Thursday at 90.

The literature award was the last of this year's Nobel Prizes to be announced. The six awards will be handed out on Dec. 10, the anniversary of prize founder Alfred Nobel's death in 1896.

Ritter reported from Stockholm. Associated Press writer Keith Moore in Stockholm also contributed to this report

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