Black Encyclopedia of the Air is the product of a rewardingly unruly artistic mind. Moor Mother, aka Camae Ayewa, is a Philadelphia-based poet, musician, artist and activist whose music inhabits various underground sub-genres (experimental hip-hop, industrial noise, free jazz). She is also a member of Black Quantum Futurism, an art project that espouses Afrofuturism — a loose-knit cultural movement that uses fantastic visions of history and futurity to free black imagination from past and present oppression. Her new album finds her reciting spoken-word, semi-rapped verses in the company of a varied cast of guest vocalists. The music is abstract hip-hop with stray snatches of melody. The results are very different from the computerised pulse of today’s chart hits — “algorithm android melodies,” as Ayewa calls them in “Mangrove”. The song places her in a dystopian “Confederate landscape” where dreams are extinguished or turned into nightmares by Sandman-style bogeymen. In previous albums, she has confronted this depleted or menacing imaginative world through improvised acts of dissonance, in particular the squalling sounds of free jazz. Black Encyclopedia of the Air takes a more fantasmic approach. Her voice and those of her collaborators dominate proceedings, a medley of rapping, singing, chanting and ghostly whispers. The music, made with Swedish producer Olof Melander, forms a background haze of jangling percussion and strung-out chords.

The results are deliberately lacking in structure, an effect that presents a different kind of challenge from the discordance of other Moor Mother releases. But it fits with the album’s idea of time and the tyranny of measurement. The final track “Clock Fight” assembles a beat-poetry litany of imprisoning timepieces — work clocks, the master’s clock, the city clock, and so on — which seem to merge into one, like the melting pocket watch in Salvador Dalí’s famous surrealist painting.