One of the earliest forms of original American music, blues music in its simplest form could be likened to African- American poetry set to music. The words and lyrics can address day-to-day struggles, love, and call-and-response exchanges. Blues is essentially based on a twelve-bar structure, usually in 4/4 time. An early form of blues was sung by the field slaves working in the South. Today, blues is a popular musical style with many variations and interpretations. Blues music is usually associated with guitar players who can also sing.