I've read the book and the recent episode of Ugly Betty made me wish i'd been able to watch the musical too.
Wicked is the retelling of the events and story of The Wizard of Oz, this time from the point of view of the witches, in particular the wicked witch of the west Elphaba and the good witch Glinda of the north. Although in this case, Elphaba wasn't so much wicked as misunderstood and a victim of situations and circumstance and glinda more self centered and vain than kind. Concepts of good and evil are also explored in the book though in shades of grey rather than the usual black and whites.
Maybe it'd be the next musical to hit our shores:
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