Confession - I did not finish this. It started blissfully, a beautifully written and well annotated history of the Judaic/Christian/Islamic faiths full of fascinating insight.
But, even then, progress was slow. And that slow progress shifted from worthwhile absorption to tedious page counting and lost thoughts.
I've made an effort, but I've taken "breaks" with at least six other books since starting this and I have to call it quits.
My advice is: read the chapters up through the establishment of Islam and peak in at the ending. You will learn a lot.
Everything else is elliptic philosophical garbage. No offense philosophers, but you take a grand idea, a jewel of thought, and record it on a broken record so the end result is something like "Revolution Number 9".