I read this book before, I think after the fourth movie came out. It has good information on where J.K. Rowling may have(*) got the ideas for names and stories for the Harry Potter Series. The explanations are fairly short for each one so that if you found one myth or legend really interesting, you would have to look it up for more information in other sources.
There is one big thing though that led me to give it a Three Star instead of Four Star rating. The book was published after the fourth book came out so all the information is only for the first four books. There are predictions of what will happen in later books which we now can confirm or debunk. I think Colbert should have waited till all Seven books came our or at least make an updated version now.
* I say may have because the book isn’t endorse by J.K. Rowling herself