Willie Dixon in the context of "Chess Records"

Chicago blues is a form of blues music that developed in Chicago, Illinois. It is based on earlier blues idioms, such as Delta blues, but is performed in an urban style. It developed alongside the Great Migration of African Americans of the first half of the twentieth century. Key features that distinguish Chicago blues from the earlier traditions, such as Delta blues, are the prominent use of electrified instruments (especially the electric guitar), and the use of electronic effects, such as distortion and overdrive.

Muddy Waters, often acknowledged as the “father” of Chicago blues, was a colleague of Delta blues musicians Son House and Robert Johnson. He migrated to Chicago in 1943, joining the established Big Bill Broonzy, where they developed a distinct style of the Chicago blues, which hit its peak around the late 1940s and early 1950s. Joined by artists such as Willie Dixon, Howlin' Wolf, and John Lee Hooker, Chicago blues reached an international audience by the late 1950s and early 1960s, directly influencing not only the development of early rock and roll musicians such as Chuck Berry and Bo Diddley, but also reaching across the Atlantic to influence both British blues and early hard rock acts such as Eric Clapton, the Rolling Stones, and Led Zeppelin. Prominent record labels such as Vee-Jay Records and Chess Records helped promote and spread the style. The Chicago Blues Festival has been held annually since 1984, on the anniversary of Muddy Waters' death, as a means of preserving and promoting Chicago blues.

Blues rock is a fusion genre and form of rock and blues music that relies on the chords/scales and instrumental improvisation of blues. It is mostly an electric ensemble-style music with instrumentation similar to electric blues and rock (electric guitar, electric bass guitar, drums, and sometimes with keyboards and harmonica). From its beginnings in the early to mid-1960s, blues rock has gone through several stylistic shifts and along the way it inspired and influenced hard rock, Southern rock, and early heavy metal.

Blues rock started with rock musicians in the United Kingdom and the United States performing American blues songs. They typically recreated electric Chicago blues songs, such as those by Willie Dixon, Muddy Waters, and Jimmy Reed, at faster tempos and with a more aggressive sound common to rock. In the UK, the style was popularized by groups such as the Rolling Stones, the Yardbirds, and the Animals, who put several blues songs into the pop charts. In the US, Lonnie Mack, the Paul Butterfield Blues Band, and Canned Heat were among the earliest exponents. Some of these bands also played long, involved improvisations as were then commonplace on jazz records. In the late 1960s and early 1970s, the style became more hard rock-oriented. In the US, Johnny Winter, the early Allman Brothers Band, and ZZ Top represented a hard rock trend, along with Led Zeppelin, Ten Years After, Chicken Shack, and Foghat in the UK.