The author, Thinley Norbu was the son of one of Tibet's most renowned and respected high lamas and yogis, Nyingma guiding light, H.H. Dudjom Jigdrel Yeshe Dorje. Thinley Norbu himself was also very highly regarded and wrote much and in much depth to give Vajrayana Buddhism a voice in the west. This book is probably his finest moment in that regard, a peerless elucidation of the meanings and depths of aspects of Ngondro, the so-called preliminary meditations and practices with its five stages encapsulating the entire path of Buddhism from renunciation, to refuge, then bodhicitta, merit accumulation, purification, and finally initiation and realization. This book is meant as a source of further pondering, it's density is said by many to be better suited to short excerpts being read and then pondered and reflected on at length. A great help for increasing the depth of one's understanding and appreciation of Ngondro.