The recordings on this posthumous Prince album weren’t originally intended for release. But they capture Prince Rogers Nelson at the peak of his powers, alone at his home studio piano, feeling his way into songs including future classic Purple Rain. It says everything about his prolific output – especially in this period – that this album is up there with many of his best releases. He certainly hits the ground running with an embryonic version of 17 Days, previously heard on the B-side of 1984’s When Doves Cry. There, the big, squeaky funky affair and joyous sound (possibly intentionally?) shrouded the pain and loneliness in the lyrics. But here, stripped down so far we hear him pleading “Turn the voice down a little” near the start, his words about a departed lover provide a raw and revelatory listening experience and a unique insight into his creative process.

Prince could play most instruments, but while his phenomenal talents as a guitarist are all over his catalogue (and currently an audible influence on St Vincent and Janelle Monáe), his skills as a pianist are under-recognised, even after his (sadly final) 2016 piano tour. But he is on fire here. Gospel, classical, funk and jazz ooze from his fingertips at will, so audaciously in the previously bootleg Cold Coffee and Cocaine you suspect the guy could have played Chopin on a watering can. Nine tracks form an unedited single take. He peels off a formative minute of Purple Rain, gets deep and bluesy on American civil war spiritual Mary Don’t You Weep, and draws a compelling skeletal embryo of Strange Relationship from Sign O’ the Times. International Lover, from 1982’s 1999, turns into a vocal masterclass. Joni Mitchell’s A Case of You offers a peek into another of his musical passions. The more hauntingly jazzy Why the Butterflies is glorious, by most standards, but obviously not glorious enough for Prince, so it stayed on the shelf. These wonderful recordings provide yet more evidence of his colossal talent, and, tantalisingly, it appears that there are still more to come.