Rarely in the history of avant-garde music has a musician laid out the modus operandi of their musical vision with such clarity and precision as Jon Hassell did on his 1977 debut, Vernal Equinox. His complex combination of electric-Miles jazz deconstruction, Hindustani raga structure, minimally abstract studio space, and Karlheinz Stockhausen’s concept of “global village polyphony” appears here more or less fully crystalized, adding up to something alien and ineffable that Hassell would later christen “fourth world.” First issued as part of a genre-defining early run of avant-garde LPs on Robert Ashley and Mimi Johnson’s Lovely Music label, Vernal Equinox is emblematic of the vaporous dissipation of genres that flowed from the late 1970s into the 1980s to undergird coming notions of global pop and world music. Like his many releases to follow, Vernal Equinox sequences a series of environmental vignettes framing Hassell’s highly experimental approach to trumpet. Aside from some light Bulcha-synthesizer processing—courtesy of David Rosenboom—on “Toucan Ocean” and “Hex,” the album is not as abstracted with effects as his later, Brian Eno-assisted experiments with harmonizer. In its more direct state, Hassell’s playing often feels strangled or turned inside out, working with a language more aligned with the animal kingdom than anything human. Pieces like “Blues Nile” and the album’s namesake centerpiece “Vernal Equinox” show the heavy influence of his raga mentor Pandit Pran Nath, with Hassell’s airy breaths sliding between the notes of a reduced scale against a mock-tambura synthesizer drone and conga from master Brazilian percussionist Naná Vasconcelos, whose minimal rhythms serve as Hassell’s main counterpoint. Vernal Equinox closes with Hassell solo—strewn of studio processing atop a hill in Caracas, Venezuela—playing against the night foley, underscoring the instrumental prowess at the core of the album’s depth.