The blues è a vocal and instrumental form of music whose original form is characterized by a repetitive structure and the use of twelve bars, the melody, the so-called blue notes.
The roots of the blues are to be found among the songs of the African-American community of slaves on the plantations of the southern states of the United States of America (the so-called Cotton Belt). The structure antiphonal (call and response) and the use of blue notes (a diminished fifth interval that considers the classical harmony and dissonance in Italy earned the nickname of the blues music tune) apparentano to musical forms of the blues' West Africa.
Many of the styles of modern popular music derived from or were heavily influenced by the blues.
Although ragtime and spirituals do not have the same origin as the blues, these three African-American musical styles were heavily influenced each other. Other genres are derivations or at least have been strongly influenced by these jazz, bluegrass, rhythm and blues, talking blues, rock and roll, hard rock, hip-hop, pop music in general.
The research of many musical artists brought the blues, jazz, and especially, in contact with many musical reality, creating new and different styles