Bob Dylan (/ˈdɪlən/; born Robert Allen Zimmerman, May 24, 1941) is an American singer-songwriter, artist and writer. He has been influential in popular music and culture for more than five decades. Much of his most celebrated work dates from the 1960s when his songs chronicled social unrest, although Dylan repudiated suggestions from journalists that he was a spokesman for his generation. Nevertheless, early songs such as "Blowin' in the Wind" and "The Times They Are a-Changin'" became anthems for the American civil rights and anti-war movements. Leaving his initial base in the American folk music revival, Dylan's six-minute single "Like a Rolling Stone" altered the range of popular music in 1965. His mid-1960s recordings, backed by rock musicians, reached the top end of the United States music charts while also attracting denunciation and criticism from others in the folk movement.Dylan's lyrics have incorporated a variety of political, social, philosophical and literary influences. They defied exisiting pop music conventions and appealed to the burgeoning counterculture. Initially inspired by the performances of Little Richard, and the songwriting of Woody Guthrie, Robert Johnson and Hank Williams, Dylan has amplified and personalized musical genres. His recording career, spanning 50 years, has explored the traditions in American song—from folk, blues, and country to gospel, rock and roll, and rockabilly to English, Scottish, and Irish folk music, embracing even jazz and swing. Dylan performs with guitar, keyboards and harmonica. Backed by a changing line-up of musicians, he has toured steadily since the late 1980s on what has been dubbed the Never Ending Tour. His accomplishments as a recording artist and performer have been central to his career, but his greatest contribution is considered his songwriting.Since 1994, Dylan has published six books of drawings and paintings, and his work has been exhibited in major art galleries. As a musician, Dylan has sold more than 100 million records, making him one of the best-selling artists of all time; he has received numerous awards including Grammy, Golden Globe and Academy Award; he has been inducted into the Rock and Roll Hall of Fame, Minnesota Music Hall of Fame, Nashville Songwriters Hall of Fame, and Songwriters Hall of Fame. The Pulitzer Prize jury in 2008 awarded him a special citation for "his profound impact on popular music and American culture, marked by lyrical compositions of extraordinary poetic power." In May 2012, Dylan received the Presidential Medal of Freedom from Barack Obama.