This is an excellent book for those who are considering, or already engaged in, a practice of toning and devotional prayer. I do not consider other reviewers' criticism of the author's Sanskrit pronunciations to have much merit. There are two points in regard to this worth considering. The first is that it is true that everywhere that Indian mantras have gone (whether Hindu, Buddhist, etc.), although the religions may have made concessions of translation as they entered new cultures, the mantras themselves are never compromised. There is an abiding belief in the sacred power of the Sanskrit language across Asia--and indeed the world. Nonetheless, this does not mean that throughout their 2,000-plus-year history, Sanskrit mantras have never been mispronounced, or that to mispronounce them somehow mitigates their spiritual efficacy. INTENTION trumps pronunciation; the most important thing is to have an open heart and a genuine attitude of gratitude. Furthermore, these mantras are to be toned--"sung"--with a great depth of resonance so that the energy centers of the body are vibrated and awakened. Due to physiological differences in the variety of human voiceboxes, of course those vibrations will re"sound" somewhat differently from individual to individual. Since there is no perfect reproduction anyway, the point is not to get someone else's rendition of a mantra right, it is to discover within yourself, on an energetic level, the particular resonation that, combined with pure intention, aligns you in harmony with your desired goals.
So don't stress out about pronunciation, gurus, satsang, etc. If lamas and gurus were so secretive about their own "perfected" vocalizations, they would never allow themselves to be recorded. If there is a particular mantra you are attracted to, by all means, track down recorded versions of it by different teachers, singers, artists, etc. (The more the better!) But more important than any of these, take the inspiration of their renditions and sing for yourself. Mantras are tools for transformation, but that transformation begins its catalysis within YOUR body's interior.
There's no dangerous misinformation here; quite the opposite, this book offers a broad palate of tools for profound transformation.