In the 1960s, rock and roll music began to change. The words became as important as the music. Bob Dylan began writing folk rock songs that many young people considered to be poetry. Dylan was influenced by folk singers and songwriters like Woody Guthrie. Dylan's early songs were about serious social issues. He wrote about war and racial injustice. Some of his songs were used as protest songs for the anti-war and civil rights movements in America. Later, Dylan wrote more personal songs. One of his most popular songs was “Mister Tambourine Man," which many people thought was a song about drug use.