Al Sijistani was a leading visionary during the Ismaili Fatimid period. This period was marked by a strong scientific spirit, a rational approach to the universe and a markedly humanistic view of mankind's key place in it. Al Sijistani was among the group of thinkers who coopted both rationalism and the philosophical sciences and answered that religious revelation reflected not merely a separate realm, but the whole of knowledge. Hence reason or the intellect was accepted as a valid source of Islamic understanding. Al Sijistani in fact argues that intellect can never be overconsumed, but thrives on being spent. Learning in a variety of ways improves the soul, giving it strength by adding to its share of intellect.
In reviewing this book,clearly the most interesting aspect of al Sijistani's thought is his combination of Neoplatonic ideas and Ismaili doctrine. This book is in contrast with others on the Ismaili movement that tend to focus on the mystical (batin) aspects of the faith. I have read this book several times and really enjoyed reading it because of its rational approach to the Ismaili faith. I was quite surprised by the sound,readily defensible, theoretical foundation that he was able to build for central and critical issues of Ismaili doctrine.