So we can express our emotions (love, hate, fear, etc.) in an art piece.
"The Scream" is part of a larger art collection other pieces that Edvard Munch called The Frieze of Life. Each had their own depiction of a moment in time of life. (Part of Expressionism period I believe)
You can find it in art history books, Wikipedia
During the renaissance artists painted or sculpted the art to look similar to everyday lives of people.
