The purpose of this book is to compare Islam and the Qur'an to Christianity and the Bible in order to persuade Muslims to become Christians. The author is a former Muslim and writes from this perspective, as one talking to his brothers about the reasons for their faith.
It's difficult for me to understand for a few reasons. Ghazoli's English is good, but his usage is just off enough that I had to re-read frequently to clearly understand what he's saying. There are also a few assumptions about what the reader already knows about Islam, Muhammad or the Qur'an; I didn't know so I missed out on some things altogether. The argumentation style isn't Western, which is the style I understand best, so that was tricky in places. All in all, I had to take a humble stance reading this, knowing that I am not the intended audience, and probably didn't really deeply understand everything that was intended in the text.
However, it was instructional. Assuming Ghazoli's information is all correct (I didn't find any reason at all to suspect it wasn't; but like I said, I have to be really humble here, knowing that there's a lot I don't know) then I was really interested in the historical information he presented about Islam, it's faith, doctrines, famous characters, writings, etc. I learned a lot!