Track one, "Machine Gun," was recorded on March 24, 1968, several months before the studio recording that resulted in the album of the same name, and features Brötzmann with saxophonists Willem Breuker, Gerd Dudek, and Evan Parker, pianist Fred Van Hove, bassists Buschi Niebergall and Peter Kowald, and drummers Han Bennink and Sven-Åke Johansson.

[1][2][3] The album is dedicated to South African bassist Johnny Dyani, who, according to Brötzmann, frequently shouted "Fuck de boere!"

"[1] The authors of The Penguin Guide to Jazz Recordings called the title track "a typically extravagant opus... which carries all before it, the trombones and saxophones making tumult over the relatively sparse backing.

"[8] AAJ's Derek Taylor described the term "de Boere" as "an archetype for any entity or group that seeks to stifle and subjugate the freedoms of others," and remarked: "The aggressive pugnacity inherent in this music is a direct response and affront to any such mongers of oppression."

"[10] In an article on "anti-fascist anthems," Stewart Smith of The Quietus described the album as "one of European free jazz's most powerful political statements," and stated that, on the second track, "the horns shriek like industrial steam valves," after which "Bailey's guitar buzzes like a swarm of cyborg insects.