In 1963, Keef Hartley joined the band Rory Storm & The Hurricanes, with whom Ringo Starr had previously drummed. After intermittent stints with John Lord in The Artwoods and engagements in Hamburg's Starclub, Hartley took part in John Mayall's album "The Blues Alone" in May 1967, on which Mayall played all the instruments except the drums himself. After that, Hartley was a permanent member of the Bluesbreakers until 1968, when the busy drummer formed his own band, The Keef Hartley Band.

With Miller Anderson (guitar, vocals), Gary Thain (bass) and Mick Weaver (keyboards) as well as saxophonist Chris Mercer, the line-up was top-class. In spring 1969, the first album "Halfbreed" was released, which served the popular genre of progressive jazz rock, in the style of bands such as Colosseum, If, Chicago and Blood, Sweat & Tears. In the same year, the Keef Hartley Band performed at the Woodstock Festival (on the 2nd day - Saturday - before The Incredible String Band). There are no audio or film recordings of their performance. Only a tape recording of a fan with fragments of some songs is said to have survived. The manager of the KHB had forbidden the recording of the concert for both audio and film. 3 months after Woodstock, The Keef Hartley Band performed at the Essen Pop & Blues Festival in the Grugahalle in October 1969, as well as at the second edition of this festival a few months later on 25 April 1970. In contrast to the Woodstock Festival, there are sound recordings of these, which have now been lovingly edited and are being made available to a wide audience for the first time in almost 55 (!) years. This is a historical document of the times, says guitarist and singer Miller Anderson, "The best thing you can hear from us live!"