I read the book first. But I suggest you don't unless you want to analyze during the musical to the point of no return. (It's inevitable.) I suggest the musical before the book, and then you can refer to the book and nitpick at what you saw later on. You will probably enjoy the musical more that way. If you do read the book, don't have that psychological, radical zeal on your minds when you walk into Gershwin.
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