Blues Rock is a fusion genre and form of Rock 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, and drums, sometimes with keyboards and harmonica).

Blues Rock can be characterized by bluesy improvisation, extended boogie jams typically focused on electric guitar solos, and often a heavier, riff-oriented sound and feel to the songs than found in typical Chicago-style Blues. Blues Rock bands “borrow[ed] the idea of an instrumental combo and loud amplification from Rock & Roll”. It is also often played at a fast tempo, again distinguishing it from the blues. One notable difference is the frequent use of a straight eighth-note or rock rhythm instead of triplets usually found in Blues.

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.

Artists like Yardbirds, Cream, and John Mayall’s Bluesbreakers in the UK and The Allman Brothers Band, Canned Heat, and Johnny Winter in the US eventually brought the sound widespread popularity. 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, Savoy Brown, and Foghat in the UK.

In the 1980s, more traditional Blues styles influenced Blues Rock, which continues into the 2000s, with more of a return to basics. Along with Hard Rock, Blues Rock songs became the core of the music played on album-oriented Rock radio in the United States, and later the Classic Rock format established there during the 1980s.

Fabulous Thunderbirds, Stevie Ray Vaughan, Georgia Satellites and Robert Cray recorded their best-known works in the 1990s and the guitarists Gary Moore, Jeff Healey, and Kenny Wayne Shepherd become popular concert attractions.

Groups such as the Jon Spencer Blues Explosion and the White Stripes brought an edgier, more diverse style into the 2000s, while the Black Keys returned to basics. Gary Clark Jr., known for his fusing of Blues, Rock and Soul, has been classified as a Blues Rock artist, with Rolling Stone’s Jonathan Bernstein referring to Clark’s albums Blak and Blu (2012) and The Story of Sonny Boy Slim (2015) as “steeped in a sleek, modern Blues-Rock production style”.

sources: discogs, wikipedia, rateyourmusic