I picked this book up as I wanted to have some sort of basic knowledge of what the movie is going to be about (this book was also my pick for BookTube-A-Thon readathon). I don't know why I expected it to be helpful, but it is really not. I haven't watched the trailer (just bits) but what I have seen gave me an idea about the movie. You don't need to read the book to watch the movie - I can tell this right off the bat. I did enjoy the book but since it is written as a textbook, it is no way as entertaining or engaging as Harry Potter books.
I think I enjoyed the introduction and some notes on the margins way more than the content itself. Rowling came up with a lot of unique magical beings and even reading the series I wasn't able to remember them all, so reading this book was a bit "meh" and it is NOT the reaction that I am used to associate with HP series.
Was it interesting? Somewhat. I think I was engrossed in the book only because I haven't read any Harry Potter books in awhile and being emerged in the world again was very exciting.
Do you have to read it to watch the movie? No. Read it if you are a hardcore fan and you want to read everything in HP universe (which means that you have probably already read this one).
I expected this book to have more notes from Harry and Ron on the margins. The fonts used for their hand writings looked a bit similar and it was hard for me to tell at times whose note that was.
It was a great pick for the readathon though as it is an easy read.
Personal rating: 3 stars