This is the book to read if you want a great introduction to Broadway and how and why musicals are written. This book will open your eyes to a lot of things you may have never thought of before and has some interesting tidbits about the history of Broadway. It will also save you the tuition money for NYU.
Mr. Viertel breaks down the structure of musicals, the songs, and why there is an order to the musical. Basically, the formula.
I believe even Broadway fans will enjoy this book. He even has a list of recommended soundtracks.
This is interesting from the first word. Enjoy!