This is not "the essentials" and it is not worth your time or money. It is more like a journalist giving you a sketchy overview from his point of view. Some basic points are acceptable, such as Sufism not being apart from Islam; however, Sufism is not just an accentuation of Islam, as Sedgwick would have you believe in the first few chapters.He completely dismisses the intellectual founding of Sufism, making it appear that someone as great as ibn Arabi is just impossible to understand and thus not worth the effort. If you are really interested in Sufism why bother with the supposed social, cultural and historical elements that Sedgwick claims. There are better Western authors to read, who have much deeper and correct insights.....If you just want to have the very basics you are better off looking into a dictionary or encyclopedia of religion. At least you will not get the subtle biases of Sedgwick to interfere with a true understanding.