It's been called the "holy grail' of Aussie rock 'n' roll recordings - a treasure trove of lost tracks by influential Adelaide band Fraternity.
That's big news in itself. But the recordings also feature the man who would become the legendary lead singer of AC/DC, the late Bon Scott.
They can now be heard as part of a box set of the band's complete recordings.
Called Seasons of Change: the Complete Recordings 1970-74, it contains tracks fully remastered from original tapes, including an entire album of new unheard songs featuring Scott.
It will be officially launched on March 18 at a 50th-anniversary concert tribute to Fraternity in Adelaide, where a special band will perform the rockers' songs live for the first time in almost 50 years.
Vince Contarino from the Zep Boys will be out front, with members of Fraternity in attendance.
Other highlights will be long-unseen footage from the 1971 Myponga Music Festival, where Fraternity performed, along with rare photos of the band.
Young promoter and fan Victor Marshall made the amazing discoveries while conducting interviews for a biography on Fraternity he has written, and which will be also launched at the show.
The cassettes and other memorabilia were in the personal collection of the band's former manager, Adelaide rock and nightlife promoter Hamish Henry, who went on to a different career in Brisbane and was seldom in touch with the former members.
At its peak, Fraternity comprised frontman Scott, bassist Bruce Howe, guitarist Mick Jurd, drummer John Freeman, John Bisset on Hammond organ, Uncle John Eyers on harmonica, multi-instrumentalist/songwriter Sam See and Mauri Berg on guitar.
While they only recorded two albums, the Doug Ashdown-produced Livestock (1971) and Flaming Galah (1972), their reputation was mighty. Teen magazine Go-Set deemed them "The Next Big Band".
Fraternity won the 1971 Hoadley's Battle of The Sounds (defeating Sherbet and Jeff St John), the first prize being a trip to London.
Memorably, they also represented the Country Arts Council on the then largest regional tour of SA, a real fish-out-of water experience for the band members, who in the spirit of the '70s, lived it up, to put it mildly.
"We went to little towns and halls where CWA ladies would be giving us scones while we were on acid," said former drummer John Freeman. "We had an official escort. I don't he'd never seen anything like us before."
Among their achievements, Fraternity were the first Australian rock band to have a devoted national prime time TV special.
At Myponga, they played alongside headline acts Black Sabbath and Daddy Cool, as well as Billy Thorpe and the Aztecs, Spectrum and others. The three-day festival, organised by Hamish, drew 15,000 people.
At various times, they performed with big names like Status Quo, Deep Purple, Free, Jerry Lee Lewis and Manfred Mann. Weirdly, they were even teamed up with 1910 Fruitgum Company, most of whose fans were too young to attend the show.
It's an impressive record for a band whose heyday only really spanned a few years.
One thing that might surprise fans of Bon, or at least those who only know him from his hard-rocking AC/DC days, is the quality and variety of his singing voice. On the prog-rock Seasons of Change, for example, it's soft and wistful, while on Somerville, it's country-infused.
John said Bon, who died in London in 1980, aged just 33, was gifted with what every would-be star dreams of - an instantly recognisable voice all his own.
"Bon was basically self-taught, but he was a real musician," John said.
Born in Scotland before migrating to WA with his family, Bon learned the drums with the Fremantle Scots Pipe Band as a boy. He also knew his way around the bagpipes, which might explain his ability with a recorder on their biggest hit, Seasons of Change.
John said that for all his wild ways, Bon was a top bloke and a loyal mate. And besides, they weren't angels, either. "People always ask me for bad stuff about Bon, but he'd give you the shirt off his back," he said.
John said that having had a great success locally with Seasons of Change, the band wanted to have a crack at America.
But Bon couldn't get a US visa because of a previous cannabis-possession conviction and other misdemeanours. So they went to the UK, where Hamish had good connections.
Despite supporting Status Quo, John said they had a lean time of things in London, with 17 people in their house and some of them having to pick up day jobs. "It was a mistake," he said. "We were the wrong band in the wrong place at the wrong time."
It was the heyday of glam rock, all glitter, dye and facepaint, and here were a bunch of bearded, scruffy Aussie pub rockers in RM Williams boots, the antithesis of David Bowie. Gigs were few, money was short and drugs were plentiful.
The end was nigh. The band went through various permutations after that: John Swan and Jimmy Barnes both sang lead after Bon left. Such were their rock chops that Barnes later said being part of Fraternity "was one of the sharpest learning curves of my life".
The band finally dissolved in 1983, leaving a huge legacy - and one about to be celebrated again. Victor says: "I hope that all the members of Fraternity will finally receive the recognition they deserve and have their real story told."
A NIGHT TO REMEMBER
Victor's Marshall's official biography of the band, Fraternity, and the CD box set will be launched at the celebration on March 18 at Thebarton Theatre, 112 Henley Beach Road, Torrensville. The show kicks off at 7.30pm, with tickets $79 for all seats. To book, visit Ticketek.
All three albums will be released as a double-vinyl set later in the year.