Masters of Meditation and Miracles: Lives of the Great Buddhist Masters of India and Tibet by Tulku Thondup
Dudjom Rinpoche, Jikdrel Yeshe Dorje. The Nyingma School of Tibetan Buddhism: its Fundamentals and History. Two Volumes. 1991. Translated and edited by Gyurme Dorje with Matthew Kapstein. Wisdom Publications, Boston.
Deity, Mantra, and Wisdom: Development Stage Meditation in Tibetan Buddhist Mantra by Jigme Lingpa
The Rise of Esoteric Buddhism in Tibet by Eva Dargyay. Second revised edition.