Dru Gyalwa Yungdrung 
The Pith Instructions for the Stages of the Practice Sessions of the A-Tri (A Khrid) System of Bon Dzogchen Meditation [EPUB ebook] 

This book 'The Pith Instructions for the Stages of the Practice Sessions of the A Khrid System of Bon r Dzogs Chen [Great Completion] Meditation’ is available in English for the very first time. Originally written by Bru r Gyal Ba G.yun G drun G (1242-1290), Geshe Sonam Gurung and Daniel P. Brown, Ph.D. faithfully translate the text from its original Tibetan under the guidance of His Holiness The Thirty-Third Menri Trizin, the head of the Bon Lineage.

A main practice manual from one of the four great lineages of Bon Great Completion meditation (rdzogs chen). These lineage teachings started with a fifty-session lesson plan by Ri Khrod, and eventually was reduced to 14 sessions by Bru r Gyal ba. This step-by-step practice manual, using 'intense means’ of pith instruction, covers three broad areas of practice.