Matrix of Mystery - Scientific and Humanistic Aspects of rDzogs-chen Thought — by Herbert V. Guenther
The first comprehensive study of the Dzogchen or Ati tradition of the Nyingma school of Tibetan Buddhism.
The Guhyagarbha Tantra - Secret Essence Definitive Nature Just As It Is — by Longchenpa
This Secret Essence Tantra is the most advanced and extensively studied tantra within the Nyingma lineage. The author includes complete explanations of the peaceful and wrathful mandalas as well as practical instructions needed to attain the four states of vidyadharahood.
Essence of Clear Light - An Overview of the Secret Commentary Thorough Dispelling of Darkness throughout the Ten Directions — by Jamgon Mipham, translated by Lama Chonam & Sangye Khandro.
This commentary on the Secret Essence by Mipham Rinpoche illuminates all the crucial points of the entire path of Secret Mantra Vajrayana.
Luminous Essence - A Guide to the Guhyagarbha Tantra — by Ju Mipham
This is a complete introduction to the world of tantric thought and practice. Embodying the essence of tantric practice, this text has been a central scripture in Tibetan Buddhism for well over a thousand years.