"Familiar Story, Excellent Narration"
Often I cringe at the idea of an author narrating his own work, but Mr. Blatty reads his book very well and he has a rich voice that seems to have been made for narration. I read the book when I was a kid and mostly remember the story from the film, so I cant speak to what was "revised and expanded" although I think I recall an interview with Blatty where he said that for the film he added a lot of the more shocking language at the request of the Director, so maybe thats it, as Regan is quite potty-mouthed here.