This book is part of 3 books with the title Gnosis, that deals with the fourth way teachings. For those unfamiliar with Gurdjieff and the fourth way I would recommend reading Ouspensky first and in particular "In search of the Miraculous".
Mouravieff brings many of the same teachings up as in the above mentioned book by Ouspensky, but he adds his own insights to certain topics and adds new concepts such as the idea of polar beings. There is a Christian flavour throughout the book with many quotes from the New Testamente. This would have to be taken with a grain of salt, especially after having read Burton Mack's excellent book "The Lost Gospel: The Book of Q and Christian Origins", where he raises serious and valid questions to the historicalness of the New Testament.
For any student of the 4'th way I would recommend reading this series of books, but be prepared that it takes more stamina to read as it to me has a more theoretical flavour than Ouspensky's book mentioned above.