I didn't actually read this entire book, because I wasn't understanding it. I checked with the original Arabic to help me out, but it didn't make much difference. Here's an excerpt which, in my case, maybe could have been distilled down to "You're too dumb to understand this book" (tongue-in-cheek, my friends!).
"The truth is that existence is one graded reality. Were it not one reality, entities would have been disparate from one another with the totality of their essences (الذوات). That would entail that the concept of existence, which is a single concept, as said, has been abstracted from disparate things qua disparate things [having no unifying aspect]. This is impossible. To explain, there is an essential unity between a concept and that to which it refers. The factor of disparity lies in existence being mental or external. Were something which is one, qua one, capable of being abstracted from that which is many, qua many, one qua one would be the same as many qua many, which is impossible."