This triple-disc installment from the Jerry Made label dedicated to archival Jerry Garcia performances hails from the guitarist's primary non-Grateful Dead vehicle circa the early to mid-'70s. Garcia flanks Merl Saunders (keyboards/vocals) as the co-leader of an improvisation-heavy aggregate that also included John Kahn (bass) and, during this particular era, Paul Humphrey (drums), Martin Fierro (sax/flute/percussion), and an anonymous trumpeter credited as "Mystery Artist." Remarkably, the September 1, 1974, show at Keystone Korners in Berkeley that is presented here was only the sixth to feature Humphrey. He and Kahn provide a consistently supple rhythm section, whose moods facilely vacillate from the delicate intimacy of "Sitting in Limbo" to the full-flight and hard-driving "Soul Roach." The latter is likewise marked by one of the better contributions from the unknown trumpet player. Within this context, Garcia's predilection and underrated jazz leanings are given plenty of room for some stretched-out exploratory excursions. Primary among them is the liberated interpretation of Antonio Carlos Jobim's "Favela" and the Fierro original "La La." Saunders steps up to the microphone for the extended "Wondering Why" (a soulful and psychedelic-tinged ballad that Geoff Muldaur would overhaul to great effect on 1975's Is Having a Wonderful Time), featuring Fierro's light and ethereal flute wisps between Garcia's ominous fretwork and Saunders' chiming electric piano. They land on an instrumental reading of the Thom Bell-penned Philly soul entry "People Make the World Go Round," which is every bit as essential as the Stylistics or the Ramsey Lewis version. Out of its ashes rises the expansive, appropriately named interplay titled "Keystone Jam." In much the same way that Garcia would channel the Grateful Dead into rarefied sonic strata, he and Saunders forge ahead into a good ol' fashioned mind melt. Contrasting the freer expeditions, the combo runs through the more structured but still well-jammed Dylan cover "Tough Mama" and a rare rendition of "Going, Going, Gone" -- both from Zimmy's most recent release, 1974's Planet Waves. So infatuated was Garcia with the former that he kept it in the Jerry Garcia Band repertoire for the rest of the group's existence. He also draws from the ample Motown songbook for infectiously fun remakes of Junior Walker's sleeper classic "Roadrunner" and Smokey Robinson's "I Second That Emotion." For the inclined, 2004's Pure Jerry Keystone Berkeley, September 1, 1974 is a no-brainer, while the faithful might liken it unto aural manna for the masses. Curious parties won't leave disappointed, either.