The blues emerged from the folk music of former enslaved Africans in the South and their descendants. The music is heavily influenced by West African culture and musical traditions, which evolved as black musicians migrated to the cities. The blues resonates throughout much of American and Western popular music, with echoes in ragtime, jazz, bluegrass, R&B, rock and roll, hipbar blues, and the use of the blue, or bent, notes. Blue notes are flattened third, fifth, and seventh notes of the major scale.
The blues is a ''state of mind'' that is often used in lyrics to describe a depressed mood. Early blues lyrics consisted of a single line repeated four times. It wasn't until the 20th Century that the more standard AAB pattern emerged. Lyrics touch upon troubled times and hardships. Of course, not all blues musicians sing about the "blues." There is the occasional "happy" song. The blues are often expressed musically through guitar, harmonica and/or voice. Those in the blues' ''state of mind'' include B.B. King.
* '''Boogiewoogie is associated with dancing.
* '''Classic female blues:''' the genre spanned from 1920 to 1929. These women were pioneers of their time because they were among the first female black singers recorded. Some of the most popular singers were Ma Rainey, Bessie Smith, Mamie Smith, Ethel Waters, and Ida Cox.
* '''Country blues:''' also known as folk blues, and refers to strictly acoustic guitar driven blues.
* '''Delta blues:''' the earliest form of blues which originated in the Mississippi Delta. Guitars and harmonicas dominate this genre, with an emphasis on rhythm and bottleneck slide.
* '''Electric blues:''' is distinguished by the use of an amplifier for the instruments. It later morphed into blues-rock.
