Rushdie's book is bizarre, and I imagine you probably need to be either familiar with Indain literature, or Rushdie's earlier work to appreciate it (and I fall into neither category). It begins with an explosion on a plane, and two men who are falling to their deaths are instantly transformed, one into a devil, the other, into the angel Gabriel. There's an enormous amount of examination over good, and evil - for example, the man who is now a devil becomes brutally treated by ordinary people, while the angel gets fawned over, and the man-angel becomes quickly vain and egotistical.
And then it gets *really* weird. The parts that got Rushdie with a death sentence on him - a 'fatwa' - were the parts where this newly created Gabriel would appear to Mohammed, but that Mohammed would force words from his mouth he had no intention of saying - the creation of the Koran. In effect, the book states that the Koran says whatever Mohammed wanted it to say.
I can't remember much more - it's been at least ten years since I read it or even opened it. I DO remember one recurring phrase, which I still sometimes use in these kinds of dialogues - "what kind of idea are you?"