History, as we know, is filled with facts, with places, names, dates, and events. History is also filled with feelings, with pain, joy, excitement, and fear. Facts are set down in books, but what happens to feelings? How can you take the pain, for example, and write it into a history book? You can't. But you can put it to music. Take the blues for example. The blues started when black musicians in the South began to sing about their hard times, those times which made them feel blue. The early blues was the beginning of other musical styles, from jazz to rock and roll. Music, you might say, is a record of feelings. Of course, facts are important: the civil rights movement, the race for space, the Vietnam War. But the feelings behind these events - the pride of being black, the excitement of a rocket blast  , the pain of a war - are also an important part of history. According to the writer's idea, what can make people feel blue?
A history book Music. History. Hard times.