Bell Labs Experimental Research Facility, New Jersey, 1978, a misty snapshot of the artist in her lair. Laurie Spiegel, dark hair streaming down to her shoulders, eyes closed, cigarette in hand, stands surrounded by a forest of sci-fi machines. Synthesisers the size of industrial freezers loom around her, a monitor hovers overhead mid-snowstorm, wire snakes around the room in a network of cat o' nine tails. There aren't any 'personal computers', not yet. She grins.

Unseen Worlds' latest fantastic reissue reveals the joy and strangeness of an artist's work, music woken from hibernation in the archive, to dazzle, drift, startle and spook. A secret history is beginning to come to light: Laurie Spiegel can deservedly take her place alongside other female pioneers in electronic music like Eliane Radigue and Pauline Oliveros, beginning a lineage that leads all the way to current innovators like Maria Minerva and Laurel Halo. That idiotic argument about electronic music being an exclusively, aggressively male space needs to die now.

In an old self-interview included alongside the voluminous liner notes, Spiegel writes, "I don't think it's a coincidence that there seems to be a relatively high percentage of women and other composers who the media might discriminate against working in electronic media". This is an illuminating answer to a phenomenon that isn't examined enough. The network of women working with electronic equipment were slipping away from an unresponsive world that had marginalised them. Machines and all their undiscovered pleasures allowed a new, otherworldly music to develop. They provided an escape from the restrictions of songs, words and scenes. Experimentation and invention took their place.

The Bell Labs facility had been dedicated to a similar kind of scientific play and exploration for a long time. The vocoder was born in one of its rooms, beginning life as a speech-scrambling device meant to encrypt the voices of Stalin and Churchill on sensitive phone-lines, before it transformed into the supernatural, frosty larynx of electro-funk and disco. While Spiegel was working there, primitive mobile phones were being constructed in secret, computers shrunk, and other electronic composers came and went, working with the same heroic mixture of patience and mixture, trying to work out what the future might sound like.

These two discs collect pieces made inside this maze of invention: elegant brittle miniatures, swirling inner-space epics and uncanny percussion pieces in one mammoth set. This is real-life cosmic music - one of its tracks was sent into orbit, carved into the Voyager Space Programme's famous Golden Record. Strangely, though, it wasn't received at first like material transmitted from the future. In 1980, no modern composition label would take it, so four of the tracks here were released by Philo, which specialised in folk.

This is weirdly fitting. Spiegel's music was formed in the rich folk and blues culture of Chicago where she played banjo and guitar and sang harmonies with her friends and her sister, and in her late teens, she lived in rural western Illinois near the Mississippi river. The sounds of that haunted wilderness still linger in her electronic works. (A soundbite on the start of her high-tech inclination: "When I was nine my father gave me a soldering iron," and taught her how to use it in his workshop.) You can catch powerful undercurrents and secret presences once you learn to listen out for them. Suddenly these tracks, intricate as spider webs, seem like nods to the quicksilver melancholy of John Fahey, whose playing Spiegel describes as "a revelation".

These dense whorls of sound emerge with a similar clarity, glittering and swooping round your ears, everything honeycombed and hi-def. Pure bright tones come cascading down in hypnotic patterns, sometimes smudging or wandering out of focus as Spiegel works the GROOVE operating system to its limit. The effect is gorgeous, the mood settled into a kind of half-awake wonder that uncannily pre-empts the interstellar swoon of Rhythim Is Rhythim's 'Kao-tic Harmony' or the dreamy sprawl of Oneohtrix Point Never's Rifts.

Elsewhere, darkness falls over two tracks composed for a dance troupe. Imagine the burial music for a king who froze to death. It's all head-injury drones, Nico's harmonium, scattered chimes, frightened mice scurrying along a pipe in the Radiophonic Workshop. These are scary pieces and untouchable reminders of the synthesiser's supreme ability to create disquiet and gloom. What kind of dance would you do to this? Probably some sort of blind staggering with sudden fits of electric panic, like a post-traumatic Pina Bausch. Their inclusion evokes Maggi Payne's recently reissued Ahh-Ahh: Music For Ed Tannenbaum's Technological Feets, another spellbinding electronic work designed to shadow electronic dance. But it's the tracks where Spiegel tries to map space in sound that she achieves the most.

Another snapshot, a fragment of an eerie memory, the inspiration for the three-part suite 'Appalachian Grove', found in the liner notes. Spiegel remembers watching as, "old mountain families played timeless modal Celtic tunes while the full moon went behind our earth's shadow in a magical total eclipse". And if she doesn't really capture the bewitching atmosphere of this account with its unspoken collaboration between cloaked light, weird ritual and ancestral song, she still sketches something extraordinary. You can feel the heat: clusters of needle-sharp synth spike round your head, everything's on fire, and sudden rumbles shake the tracks' edges. Or 'East River Dawn', with its Polaroid glow that precisely captures the woozy feeling that comes at sunrise, watching morning slowly slip into focus.

Last of all comes 'The Unquestioned Answer' which is just gorgeous. Everything's delicately spaced and lit just so, greens and reds blossoming with Rothko warmth, the sun gently falling. A superb introduction to a singular artist. This is somewhere to get lost for long time.