Emerson, Lake & Palmer's most successful and well-realized album (after their first), and their most ambitious as a group, as well as their loudest, Brain Salad Surgery was also the most steeped in electronic sounds of any of their records.
The main focus, thanks to the three-part "Karn Evil 9," is sci-fi rock, approached with a volume and vengeance that stretched the art rock audience's tolerance to its outer limit, but also managed to appeal to the metal audience in ways that little of Trilogy did.
Indeed, "Karn Evil 9" is the piece and the place where Keith Emerson and his keyboards finally matched in both music and flamboyance the larger-than-life guitar sound of Jimi Hendrix.
This also marked the point in the group's history in which they brought in their first outside creative hand, in the guise of ex-King Crimson lyricist Pete Sinfield.
He'd been shopping around his first solo album and was invited onto the trio's new Manticore label, and also asked in to this project as Lake's abilities as a lyricist didn't seem quite up to the 20-minute "Karn Evil 9" epic that Emerson had created as an instrumental.
Sinfield's resulting lyrics for "Karn Evil 9: First Impression" and "Karn Evil 9: Third Impression," while not up to the standard of his best Crimson work, were better than anything the group had to work with previously -- he was also responsible for Emerson's choice of title, persuading the keyboardist that the music he'd come up with was more evocative of a carnival and fantasy than the pure science fiction concept that Emerson had started with.
And Greg Lake pulled out all the stops with his heaviest singing voice in handling them, coming off a bit like Peter Gabriel in the process.
And amid Carl Palmer's prodigious drumming, it was all a showcase for Emerson, who employed more keyboards and more sounds here -- including electronic voices -- than had previously been heard on one of their records.
The songs (except for the light-hearted throwaway "Benny the Bouncer") are also among their best work -- the group's arrangement of Sir Charles Hubert Parry's setting of William Blake's "Jerusalem" manages to be reverent yet rocking (a combination that got it banned by the BBC for potential "blasphemy"), while Emerson's adaptation of Alberto Ginastera's music in "Tocatta" outstrips even "The Barbarian" and "Knife Edge" from the first album as a distinctive and rewarding reinterpretation of a piece of serious music.
Lake's "Still...You Turn Me On," the album's obligatory acoustic number, was his last great ballad with the group, possessing a melody and arrangement sufficiently pretty to forgive the presence of the rhyming triplet "everyday a little sadder/a little madder/someone get me a ladder." And the sound quality was stunning, and the whole album represented a high point that the trio would never again achieve, or even aspire to -- after this, each member started to go his own way in terms of creativity and music.