Record label mogul Allen Klein, who played a key role during the bitter demise of the Beatles, has died in New York on Saturday after suffering from Alzheimer's disease. He was 77.
During a career spanning more than 50 years, the former New Jersey accountant secured a fortune as one of the savviest and most infamous players in the music business.
He managed the Beatles from 1969 at the behest of John Lennon, Ringo Starr and George Harrison.
Paul McCartney was fiercely opposed to Mr Klein, preferring the legal expertise of his high-powered father-in-law Lee Eastman.
The feud set the scene for the court battle that led to the group's dissolution.
Allen Klein later reunited with Harrison to organize the all-star Concert for Bangladesh show in 1971. It took a decade for the funds to reach the refugees because of complex tax problems. He also continued to work with Lennon and Yoko Ono.
He also managed the Rolling Stones during the 1960s and ended up owning the rights to their recordings and copyrights from that decade, to the eternal regret of Mick Jagger.
He first made his mark in the music industry by auditing record labels on behalf of clients such as Bobby Darin and Connie Francis.
When he invariably found that they were owed royalties, he took a percentage of the difference as a fee. He also managed Sam Cooke, helping the R&B star set up his own label and publishing company.
Mr Klein's family-owned ABKCO Music & Records also handled the recordings of such artists as the Animals, Herman's Hermits, Bobby Womack, Marianne Faithfull, the Kinks, Chubby Checker, Bobby Rydell and many others.
He is survived by his wife and three adult children.