Music industry giants Sony are said to have settled out of court earlier this year after a decade-long battle with the Edinburgh pop outfit.
They sold more than 120 million albums in they heyday, but were left virtually empty-handed in the wake of bitter legal wrangles.
Author Simon Spence spent a year investigating the troubled background of the band for his book, The Dark History of the Bay City Rollers.He says says he discovered a strict confidentiality agreement is in place over a deal, which key members of the band are believed to have won with Sony, parent company of their label Arista Records.
At one point the Bay City Rollers, whose hits included Remember, Shang-a-Lang, Bye Bye Baby and Saturday Night, were reported to have been owed more than £70 million in unpaid royalties.
His book charts the efforts of the various band members - including Les McKeown, Eric Faulkner, Stuart Wood, Alan Longmuir and Derek Longmuir - to recoup their royalties after being plunged into financial ruin when the Rollers split in the early 1980s.
It also lifts the lid on the drug and alcohol addiction problems which dogged the group and the influence of their long-time manager Tam Paton, who was put behind bars for gross indecency against two teenage boys.
Spence says the key members of the Rollers received just one previous royalty payment of £120,000 each when a previous out-of-court settlement was reached in 1987. A new lawsuit was launched 20 years later.
He writes: “In early May 2016, I was told by a reliable source, that the band and Sony had settled out of court. There had been no concrete developments in the lawsuit reported by the media.
“The settlement figure was rumoured to be $3.5 million and the band members were said to have come away with just about £70,000 each. It seemed a believable, if rather limp, ending to their epic struggle with the record industry.
“After all, there had been a similar amount of money on offer from the label for many years. It had been tens of millions they had been chasing.”
Spence said of his book: “I wanted to write a classic rock n roll book about the pop business, an expose.
“It is one of the most depraved and debauched stories in rock history and I was amazed there had not been a detailed book about it.
A new wave of “Rollermania” was triggered last September when a BBC Scotland documentary charted the highs and lows of the band.
Weeks later Les McKeown, Stuart Wood and Alan Longmuir revealed they would be reuniting for a series of festive shows. They then played the T in the Park festival and will be at the Hydro in Glasgow in December.