I have just received a copy of the book about the making of the show, The Road to Broadway and Beyond Disney Aladdin: A Whole New World by Michael Lassell.
This is a beautiful book and a model when it comes to books about musicals. All is in there: great interviews, beautiful concept art, great behind-the-scenes photos. If you are into Broadway musicals, especially Disney ones, this book is definitely for you. It is a home-run.