I agree completely with the two previous reviews, and have only one point to add. For students of Tibetan Buddhism who are actually doing the Guru Yoga practice of the Longchen Nyingthig Ngondro, this is a priceless handbook to suppliment and remind them of their own teacher's instructions. It makes an excellent companion to "Words of My Perfect Teacher", Patrul Rimpoche's guide to the entire Ngondro practice.
Whether a newcomer to meditation, or more specifically to guru yoga in the Tibetan Nyingma tradition - or a somewhat more experienced practitioner, this book is extraordinary. If you are new to this kind of mediation, I would say it is one of the best guides into it (as a follow-up to your master's introduction and empowerment, of course). If you have practised guru yoga for a while, you have in your hands a treasury of inspiration. You will be able to dig into it again and again, and still go deeper. If a book can transmit the wisdom-mind of a buddhist master, this is it! H.H. Dilgo Khyentse Rinpoche is right there with you.