Bob Dylan (legally Robert Dylan, born Robert Allen Zimmerman, May 24, 1941) is an American singer-songwriter. Often regarded as one of the greatest songwriters of all time, Dylan has been a major figure in popular culture during a career spanning more than 60 years. Much of his most celebrated work dates from the 1960s, when songs such as "Blowin' in the Wind" (1963) and "The Times They Are a-Changin'" (1964) became anthems for the civil rights and antiwar movements. His lyrics during this period incorporated a range of political, social, philosophical, and literary influences, defying pop music conventions and appealing to the burgeoning counterculture.