This book is elegantly written with great historical depth and sensitivity. Dr Nasr is Shi'a and teaches at the Naval PG School.
I liked this book better than the similar one by Yitzhak Nakash because it was focussed on tradition and culture more than up to the minute politics. For that, Nakash's book is quite good. Nasr is also a whizbang of a prose stylist, while Nakash is not.