The book ended up being worthless as it had two duplicate sections of approximately 70 pages each while it was missing 70 pages of text that should have been there.
Unfortunately, this issue was not discovered until my son was 300 pages into the book, necessitating a trip to a local bookstore for a replacement. This problem was not readily identifiable upon initial inspection of the received book and by the time it was discovered we did not have the time to return it and re-order.
I don't see any way to prevent this from happening again, so I probably won't be buying any more books through you.