This is a very strange book indeed. It challenges all the established notions of the causes of historical events. It does not read like a cultist account. After reading it I think anyone will find his thoughts about the nature of history will change, even if he thinks all or most of the contents are nonsense.
Clearly the author has been closely associated with the modern expressions of the Sufi tradition.
The references within the text give the reader links to much other material and show signs of genuine scholarship - quite different from the run of the mill cultist books which fill the shelves of so many bookshops.
Among the topics which the western reader may find startling are thoughts about the origins of western science, Shakespear, much of western literature and its relation to what is often thought of as 'eastern' literature. Even the current decline of religion and the rise of drug taking are mentioned as being possibly the results of causes quite unsuspected by the average person.
I have been reading this book since it was first published in 1983 and still find new thoughts in it.