If you know an Azymuth album, it’s probably this one — thanks, in all likelihood, to the modest but memorable cult crossover of “Jazz Carnival,” which hit the UK top 20 singles in 1980. That number isn’t just the biggest hit of this Brazilian fusion outfit’s decades-long career, it’s one of the most joyous disco-jazz cuts ever committed to tape. And it plays to all their strengths: a samba-marinated floor-filler where José Roberto Bertrami’s skittering, jagged-parabola keyboard riffs and contemplative-yet-frenetic solos on an entire warehouse’s worth of synths and organs explore entire galaxies over Alex Mahleiros’s breath-snatching gallop of a bassline and Ivan “Mamão” Conti’s fluid, powerful drive on drums. “Jazz Carnival” might be the only song on this (or any) album that goes that hard into MPB-disco-fusion sublimity — though the more compact and to-the-point cuts “Avenida Das Mangueiras” and “This Exists (Existe Isto)” come close — but the mellow vibe of the Return to Forever title cover is a bit more characteristic of the charms Light as a Feather possesses. That one’s a summery glide where the placid, sun-kissed atmosphere just barely conceals the fact that the trio’s playing their asses off even during the relaxed numbers, as though they can’t help showing off the potential to explode out of their constrictions. Their acknowledgement of the relationship between MPB and soul-jazz is strong enough that “Fly Over The Horizon (Vôo Sobre O Horizonte)” simultaneously recalls Getz/Gilberto and That’s the Way of the World, while the further-flung excursions into spacious, airy samba-funk (“Partido Alto”) and Weather Report-style new wave-y art-jazz meditations (“Young Embrace (Um Abraço Da Mocidade”)) keep their versatility at the forefront.