Most musicians hate fans to hear their nascent demos, those early trial balloons punctured by bum notes and bad decisions. Unfortunately, the biggest stars often don’t have a choice in the matter – especially if they happen to be dead. Such a fate befell Amy Winehouse when, last week, one of her producers took it upon himself to release an early demo he had of the singer, defying the artist’s estate, which had destroyed the initial, inferior work they possessed.

By the same token, when true fans hear those early tests, they often appreciate the rare peek into the artist’s evolution. More, they usually know how to contextualize it within the body of their idol’s better-honed works. That’s good considering the number of demos that have slipped out over the years, including many that document music which pre-dates a major artist’s stardom.

Here’s a look at 10 of the most intriguing:

Madonna

Before she found a buoyant dance-pop sound for her 1983 major label debut, Madonna experimented with a host of other styles, captured on scores of demos that surfaced later. One of most fascinating contains a turbo-charged punk outburst titled Safe Neighborhood. The whipping guitars and wiry bass that fire the song fit snugly with the dominant sound of downtown New York at the time Madge moved there in 1978. Fuzzy facts surround the origin of the recording. Allegedly, it dates from 1980, around the time the singer played in a band named Emmy with then boyfriend Stephen Bray. But it isn’t included on an album Bray released in 1997 titled Pre-Madonna, nor on the other Emmy-identified demos that have since leaked. The Bray disc includes early demos of two songs from Madonna’s official debut, Everybody and Burnin’ Up. Safe easily outdoes Burnin’ as her most rock-charged performance ever. It’s a blast to hear Madonna give Lydia Lunch a run for her money with her shrieks. Another fun demo, for Love Express, captures Madonna performing solo, with just voice and acoustic guitar. It’s a fleet rockabilly romp, in the mode of prime Everly Brothers.

Kurt Cobain/Nirvana

In 2015, Universal Music domesticated a wide range of scratchy demos taped by Kurt Cobain in his formative years. Titled Montage of Heck: The Home Recordings, the disc served as soundtrack to the like-named documentary film. Amid the dross, that set does contain a few interesting bits, including a cover of the Beatles’ And I Love Her, and a rough run at Been A Son, later cut by Nirvana for their Blew EP. Other dribs and drabs have slunk out over the years, most of negligible interest. The latest surfaced just two months ago, purporting to be the first demo ever cut by Nirvana. The audio is woefully muffled but the performance shows some verve, capturing the fledgling band as they run through early pieces like Blew, Love Buzz and an especially roiling Spank Thru.

Radiohead

Given the obsessive nature of Radiohead fans, it’s small wonder they’ve ferreted out no end of evidence of the pre-Pablo Honey band, heard in various iterations. The oldest one dates back to 1986, when they performed under the name On A Friday. It’s nearly impossible to draw a line between what we hear in these recordings, cut at the Abingdon School, to prime Radiohead. For one thing, there’s not a trace of the later artiness. A song like Fragile Friend has the zip of pure jangle-pop. Its riff sounds like something Johnny Marr might’ve devised for the Smiths. The music also has a wider, if more conventional, melodic range than the band’s celebrated work. It’s often faster too. In 2006, another demo collection, dating from 1990, slunk out, capturing the days when the band billed itself as Shindig. The opening song, Climbing Up A Bloody Great Hill, has a mid-’60s go-go feel that would have fit right in on the Sunset Strip of the day. There’s even a Farfisa organ pumping away. Who knew such mopey souls could sound so peppy?

Adele

In her mid-teen years, Adele asked a friend to film a video/demo of her performing, which they then uploaded to My Space. The 2006 live performance, of the song Daydreamer, features the singer accompanying herself on acoustic guitar. Two years later, the same song opened Adele’s winning album debut, 19. However blurry the visual, and hazy the recording, in the vocals you can hear much of the purity and range of the great Adele to come.

Sting

Three years before he formed the Police, Sting played with a cool fusion quartet, based in Newcastle, named Last Exit. A respected act, Exit convinced Virgin to finance a demo, though it wasn’t released in its day. Years later, a set titled First From Last Exit surfaced and became a collector’s item. But it didn’t include one of the band’s most appealing pieces – a 1974 cover of Neil Young’s Don’t Let It Bring You Down. Cut at Impulse Studios in Newcastle, their version puts a sensual spin on Young’s arid ballad. It sounds like something left off Traffic’s Low Spark of High Heeled Boys. Sting’s reedy voice provides a nice corollary to Young’s, while his bass lines flirt with a fine electric piano solo by Gerry Richardson. The jazzy sound wouldn’t be far out of place on Sting’s first solo album, The Dream of Blue Turtles, issued a decade down the line.

Television

Because they were primarily a live band, Television put a different spin on every one of their performances. Which means there’s a freshness to any demo you’ll find from this pioneering 1970s New York foursome. On YouTube, you can find a recording of their signature piece Marquee Moon, cut three years before it would serve as the title track of their 1977 official debut. The seven-minute take runs faster than the official one and also features sterling solos from guitarists Tom Verlaine and Richard Lloyd. There’s also a collection of demos from ’74-’75 that runs nearly 50 minutes and features 11 tracks, including the song Little Johnny Jewel, which never made it to an official TV album.

Queen

Before they crowned themselves Queen, three of its four members performed as Smile (minus only bassist John Deacon). At the time, Freddie Mercury still went under his original surname Bulsara, though not his given name (Farrokh). A key song Smile demo’d in 1972, Polar Bear, penned by Brian May, survives. A gentle ballad, it provides a sweet showcase for Mercury’s aching falsetto. Queen considered releasing their own version of the song on their self-titled debut in 1973. Considering the fragility of the piece, it’s best that they didn’t.

Eminem

It’s barely three minutes long, but the down and dirty demo Eminem made of The Kids early in his career has an immediacy that reveals someone young, hungry and already focused. The dark, thumping bass line isn’t bad either.

Justin Bieber

Justin Bieber owes his first break to his raw demos. The singer’s ambitious mother/manager started throwing up rough clips she shot of her kid on YouTube, as he crooned ballads that had been hits for stars like Chris Brown, Usher and Brian McKnight. One, for the song Back At One, captured the Bieb in the bathroom sporting a most unfortunate haircut. In 2007, So So Def executive Scooter Braun stumbled on one of those YouTube clips and chased the singer down for an audition. That led to a meeting with Usher, who signed the singer. The demos prove Bieber has a decent voice, though it’s hard to imagine him as a sex symbol, even to teens. He was 13 at the time of the demos, but looks no older than five.

Skrillex

The same route to stardom that jump-started Justin Bieber’s career lifted Skrillex (born Sonny Moore). In 2010, the DJ put a demo EP up on his Myspace page that opened with the assertive track My Name Is Skrillex. Boosted by his tireless club performances and grassroots marketing, Skrillex’s music found an audience. It escalated so quickly that an EP he issued six months later, Scary Monsters and Nice Sprights, cracked the Billboard chart and, eventually, went platinum. Consider it proof that, for modern artists, demos can have even greater potency than official releases.