Artists like B.B King, Muddy Waters, and Bessie Smith are notable Blues Artists.
There are unique elements of the blues. First is the blue note which is a note that falls between two adjacent notes in the standard Western division of the octave, most often the third or seventh degree on a scale. Second, a bottleneck which is a technique where a guitarist slides a glass/metal neck from a bottle across the strings to reconstruct the timbre.