Scorching set of unreleased live tracks from one of the 70s' most underrated jazz-rock bands. Led by guitarist Gary Boyle and featuring Hugh Hopper on bass, like its namesake the quartet was indeed that rare element on music's then periodic table, redolent of a time when musicians linking jazz sensibilities to rock's sinew weren't casually dismissed, before critics were ridiculously writing off such music as empty virtuosity (and from which, frankly, most of the music wrung its bulldog inertia), as prog began its descent largely back into the underground and sheer brazen musicianship trumped songwriting. It was a time when quantitative energy and bravado matched wits with intellectual prowess, when the idioms of jazz and rock produced strange bedfellows that, for the most part, reveled in post-coital sonic ecstasy.

Isotope's progeny of course continues forward to his day, Boyle having recently issued some more leisurely-paced music and Hopper always with numerous irons in the fire, but with Isotope they masterfully balanced order and chaos. Boyle's technique definitely arises out of the McLaughlin school of shredded nylon, fingers parsing a hundred-notes-a-second, but as scorching as his playing is, saying it was all flash and little filigree is to vastly under-appreciate Boyle's worth as a writer. True, riveting solos are in great abundance here � witness both included versions of their signature tune "Attila," where Boyle's initial melody gets subsumed into his tornadic fretwork, the kinetic energy of which hurls him right off the reservation. But Isotope were first and foremost a quartet, well-coordinated, in sync, capable of rhythmic hairpin turns and mini-crescendos that often crested and crashed numerous times in the same piece. Keyboardist Laurence Scott and Nigel Morris shake the foundations on the opening version of "Illusion," a flurry of electric piano igniting the surrounding atmosphere while Morris's freight train drums keep hyperdrive time amidst Hopper's over-amped bass and Boyle's coruscating licks.

Midway through the nine-minute version of "Spanish Sun", erupting out of Boyle's molten metal phrases, Hopper initiates a creepy-crawly bass sequence that Robert Rodriguez seemed to have "co-opted" to underpin the theme for his film Planet Terror, hot as a sizzling jalape�o, with an aftereffect every bit as formidable. That the group can keep momentum building and achieve an ideal on-site equilibrium between them is nothing short of astounding � it bespeaks of a level of musicianship that is often overlooked once jazz-rock discourse gets past the wow factor. Golden Section categorically dispenses with flip analysis and simply gets down to it, a glorious document of unmitigated intensity by a group that, at the time, operated at the peak of their powers.