Half a century ago, Bob Dylan shocked the music world by plugging in an electric guitar and alienating folk purists. For decades he continued to confound expectations, selling millions of records with dense, enigmatic songwriting.

Now, Mr. Dylan, the poet laureate of the rock era, has been rewarded with the Nobel Prize in Literature, an honor that elevates him into the company of T. S. Eliot, Gabriel García Márquez, Toni Morrison and Samuel Beckett.

Mr. Dylan, 75, is the first musician to win the award, and his selection on Thursday is perhaps the most radical choice in a history stretching back to 1901. In choosing a popular musician for the literary world’s highest honor, the Swedish Academy, which awards the prize, dramatically redefined the boundaries of literature, setting off a debate about whether song lyrics have the same artistic value as poetry or novels.

[ Our pop critic on Bob Dylan, the musician | Our book critic on Dylan, the writer ]

Some prominent writers celebrated Mr. Dylan’s literary achievements, including Stephen King, Joyce Carol Oates and Salman Rushdie, who called Mr. Dylan “the brilliant inheritor of the bardic tradition,” adding, “Great choice.”