As one who has been on a journey toward Orthodoxy for nearly a year, I had read about the Jesus Prayer in other books and when I saw this work by Archimandrite Lev Gillet, I immediately made the purchase.
Fr. Gillet is a very interesting individual, he was not raised in the Orthodox tradition but came to Orthodoxy through his own study over numerous years as a Roman priest. The first part of his work tells his story, which I found quite fascinating. Fr. Gillet came to Orthodoxy in the early 20th century which was not a time of numerous converts to the Eastern Church.
The heart of this work, is the history and theology of the Jesus Prayer, while very interesting, is a very heavy read for those who do not have a theological background. Conversely, those who have a solid theological grounding, who have studied Orthodoxy and are familiar with the Jesus Prayer, which I believe is at the heart of individual prayer for devout Orthodox Christians, will find this book worthwhile and if they have not taken upon themselves to use the Jesus Prayer as part of their prayer life; they will after reading Fr. Gillet's work.
The Jesus Prayer, is not for those starting their search into Orthodoxy especially if their theological knowledge is sparse. There are other books for searchers.
This work will remain in my library, to be read again at a later day, when I have a fuller appreciation of what it means to be a devout Orthodox Christian.