This book actual title is : The Philosophical View of the Great Perfection in the Tibetan Bon Religion. The Great Perfection (Dzokchen) originated in the Bon Religion of Tibet and was adopted by buddhism

Followers of the Bon religion maintain that its tenets were first expounded by the Teacher Shenrab Mipoche, who is considered to have made his appearance on earth much earlier than the Buddha Sakyamuni,and was born in and ruled a country to the West of Tibet 

After Shenrab Mipoche entrusted his teachings to worthy successors, the Everlasting Bon is believed to have spread from that country toward the East, reaching India, China, the kingdom of Zhang Zhung and from there Tibet. The kingdom of Zhang Zhung played an influential role in the history and culture of Tibet. (the Spar language) was the language from which numerous texts, including those of the Great Perfection (Dzokchen), are said to have been translated into Tibetan. Zhang Zhung priests and masters were invited to Tibet to offer their wisdom and their supernatural skills. Eventually, around the seventh/eighth centuries A.D., the kingdom of Zhang Zhung was conquered and annexed to the then expanding Tibetan empire.

Bon enjoyed royal patronage in Tibet until the second half of the eighth century A.D., when Buddhism was adopted as the official creed. Bon lost its recognition and support at the highest level and its followers, particularly within the established religious elite, had no choice but to convert or go into exile. Bonpo texts were hidden so that they could be retrieved and revealed later, at more favorable times."