The 2017 release Thunder of the Gods contains three previously unreleased Sun Ra recordings originating from the late '60s and early '70s. The first side is a 23-minute portion of a performance at Slug's Saloon in New York, where the Arkestra held an 18-month weekly residence. They start off with "Calling Planet Earth," beginning with an intergalactic cry before tumbling into freewheeling cosmic improvisation. The performance was captured with two microphones placed at either end of the stage, and while it's such a simple recording setup, it goes a long way in preserving the subtleties and nuances in the musicians' performances. Eventually it segues into "We'll Wait for You" (which, like "Calling Planet Earth," featured in Sun Ra's film Space Is the Place), with June Tyson's booming voice ecstatically delivering Ra's celestial poetry. After another period of full-band fury, Ra plays a synthesizer solo that gradually becomes heavier and louder, verging on harsh noise and filled with mind-twisting manipulations. The entire performance is fascinating, and an excellent summation of the live powers of both the Arkestra and Ra as an individual. The other two selections on the disc are mono studio recordings taken from the same period as the Strange Strings album, so named because Ra provided the musicians with stringed instruments that they were unfamiliar with. He instructed them to start playing, but not how or what to play. As such, it's some of the most challenging music produced by the Arkestra, filled with atonal scraping, clawing, scratching, clattering, and slapping. Fascinating stuff for hardcore fans, but for most other listeners, the first half of the album is more likely to be played more than once.