Andrew Lloyd Webber, who I met in 1999).
Reason #1: The utter absence of a hetero-romantic plot, almost unheard-of in musical theater.
It's a Mod version of the picaresque adventures of Joseph (from the Bible), favorite of his father, given a Coat of Many Colors.
His brothers, jealous, set out to kill him, but have a change of heart and sell him to slave traders instead. He ends up in Egypt -- depicted as a glittery Las Vegas -- as a slave to sleazy merchant Potiphar.
Potiphar's wife tries unsuccessfully to seduce him -- "I don't believe in free love," he yells in 1960s slang. Or maybe he doesn't particularly care for girls.
Falsely accused of attempted rape, Joseph is thrown in prison, where he begins interpreting other prisoners' weird dreams, thus drawing the attention of the Pharaoh (an Elvis-like pop star). Pharaoh makes Joseph his right-hand man. The brothers arrive, and Joseph toys with them a bit before reconciling.
There have been innumerable revivals, in Britain and the U.S., with Joseph played by James Royce Edwards, Paul Jones, David James-Carroll, Bill Hutton, Mike Holoway, David Cassidy, his brother Patrick Cassidy, Jason Donovan, Lee Mead, and Keith Jacks (top photo). Former teen idol Donny Osmond starred in the 1999 movie version.