Joni Mitchell, Gordon Lightfoot, and Revolver

In the 1960s, Joni and Chuck Mitchell had a 5th floor apartment in
Detroit which served as a musical salon.  Musicians passing through town
would stop in and debut their new songs for each other.  One such
performer was Gordon Lightfoot.  When the Mitchells embarked on a tour,
they invited Lightfoot to stay at their place -- with one condition:  He
had to listen their copy of the Beatles' Revolver.  "And I did,"
Lightfoot recalled later.  "It was such a damned good album that I got
hooked.  So Joni got me turned on to the Beatles, which I'd been
resisting."
-- From Nicholas Jennings' Lightfoot biography