Written in the mid-nineteenth century, this is not a typical 20th- or 21st-century "spiritual self-help" kind of book, although the subtitle is "The classic guide to the practice of unceasing prayer as found in The Way of a Pilgrim."
Very repetitive, this is nonetheless a valuable book for anyone interested in getting into more theological and practical detail about the Jesus Prayer. Idefinitely would recommend The Way of a Pilgrim as a first stop, and if that doesn't interest and inspire a reader, then I wouldn't think this would be of much use. Brianchaninov at one point suggests that pursuit of the Jesus Prayer is more a call than one among many options; whether that's accurate or not, this would seem to be slightly more advanced material.
One of the most interesting aspects of this book was, for me, reading it after Irina Tweedie's Daughter of Fire and seeing some very interesting comparisons with her discussions of kundalini energy, vibrations, and the Sufi la illallah practice (repeating the name of God devotionally, I think), and this book's descriptions of possible responses to a deep and intense practice of the Jesus Prayer. That bears more detailed reading, but nevertheless, although I'm sure Brianchaninov would be horrified at the idea, there are many aspects that are quite congruent with mystical paths of other traditions. After all, the person practicing is seeking union with Christ, for which pure attention and presence are required.
The things that made it tiresome at times for me were (1) the claim that the Jesus Prayer is for all Christians, not just monks, alternating with the assumption that the reader is a monk living in a monastery or even hermit dwelling, and warning of the dangers of unsupervised practice -- then claiming that there are really no great spiritual directors left, so you're never going to find one anyway; and (2) the repetition and repetition and repetition over and over and over again. I read a lot of spiritual classics and I think I could say that most of them are repetitive and rely on frequent use of scriptural quote within sentences (in this book, there were 10 in the first 9 pages), and I usually enjoy that, but perhaps Brianchaninov's writing isn't particularly compelling to me.
The notes and bibliography (all provided by translator and editor, I'd guess) are particularly good; they reference other sources I'd like to follow up on. Interestingly, they mostly point to Greek Orthodox sources (the Philokalia and other writings) rather than the Russian Orthodox literature (such as the Little Russian Philokalia) volumes, even though Brianchaninov is Russian. The exception being, of course,The Way of a Pilgrim, which is also published in a very good critical edition put out by the Classics of Western Spirituality series (although this is clearly Eastern spirituality, not to nitpick) called The Pilgrim's Tale (which sounds very Chaucerian, doesn't it? and in fact there's an old anti-monastic poem, middle-English, I think, that is entitled "The Pilgrim's Tale.").