Wow, thanks for the quick input! That saves me a good bit of money. I'm curious, why do you call it a crackpot theory? The person who showed me this book is well-educated and seemed to validate its contents as well-researched.
Before I begin digging into this though, I would also like to know what is the huge body of historical linguistics that this book is "up against" so that I can compare studies. Because as far as I currently understand it, there is no evidence for the origin of the Hebrew language outside of the Tanakh which can be traced only as far back as the Greeks invading Egypt.
Additionally, if Hebrew is the afroasiatic language you're referencing, I would think there should be more evidence to support its existence than we have found up to this point - more African peoples speaking it, older archaeological evidence of Jews in Africa, etc.
And if there is no consensus on how to connect these languages, wouldn't a text like this be all the more important? I mean, most learned people agree that humanity's origins start in Africa so it's not all that far-fetched to believe that these different languages are not so... distinct.
I say all of this because my own interests have led me to believe that Greeks and Romans conspired to dominate the world through our current religious order. Among my own findings I've uncovered many of the controversies behind the big three religions and they definitely seem to be connected to one source...
A book like this seems like it might hold some of the more important puzzle pieces I would need to further confirm my previous research.
Language, ethnicity, and religion are different things. Don't conflate them.
Linguistics is a very broad field of study. Forgive me if the analogy sounds condescending, but your question is like a horoscope reader asking "What is this huge body of research called astronomy, can you please point me to it?" Here is a bibliography with a focus on the historical linguistics of the Afroasiatic languages.
It is possible that Greek and Hebrew descend from a common ancestor, but this is not the same idea as "Hebrew is Greek." If they do, the evidence for it is weak and inconclusive, which is why there are very few linguists who claim to know this. I call this particular theory crackpot because in the very short time I spent looking at it, it was clear that the author and his proponents have an agenda that drives their thesis to ignore entire branches of scholarly inquiry that contradict what they prefer to be true.
Most people don't generally encounter linguistics in their studies, so it can be harder to spot dubious claims in that area. You seem like a smart and curious individual though, so I encourage you to read up on the field of historical linguistics while tackling this book. If you found out about this rare tome, I have no doubt you can figure out what books are good intros to historical linguistics.
All the best to you.