Bob Dylan is an American singer-songwriter. Often considered to be one of the greatest songwriters in history, Dylan has been a major figure in popular culture over his 60-year career. He rose to prominence in the 1960s, when songs such as "The Times They Are a-Changin'
" (1964) became anthems for the civil rights and antiwar movements. Initially modeling his style on Woody Guthrie's folk songs, Robert Johnson's blues and what he called the "architectural forms" of Hank Williams's country songs, Dylan added increasingly sophisticated lyrical techniques to the folk music of the early 1960s, infusing it "with the intellectualism of classic literature and poetry". His lyrics incorporated political, social and philosophical influences, defying pop music conventions and appealing to the burgeoning counterculture.