Allen Klein
Klein played a role in the breakup of the Beatles. He impressed John Lennon enough to sign up with him overnight, and Lennon persuaded George Harrison and Ringo Starr to go along. Paul McCartney, though, decided to let his wife Linda's father Lee Eastman become his manager. Eastman and Klein did not get along, and Eastman treated Lennon and his wife Yoko Ono poorly. Disagreements on what the Beatles should be doing with their company Apple Corps, and their own business interests, helped to tear the band apart.