The preliminary practices establish the foundation for the more advanced and esoteric Vajrayana sādhanā which are held to engender realization and the embodiment of Dzogchen, Heruka and Mahamudra.
The special or extraordinary kind of preliminaries consist of:[citation needed] Traditionally ngöndro practice is done for the enlightenment of the spiritual aspirant and for the benefit of all sentient beings.
[citation needed] Each of the four main schools of Tibetan Buddhism—Gelug, Kagyu, Nyingma and Sakya have variations as to the order of the preliminaries, the refuge trees visualized, the lineage gurus and deities invoked, and prayers.
[citation needed] Before receiving advanced tantric practices from a qualified spiritual teacher a ngöndro usually must be completed and fully internalized.
The Longchen Nyingthig (Wylie: klong chen snying thig: "Heart Essence of the Vast Expanse") is a terma cycle revealed by the master Jigme Lingpa.
It is particularly known and loved for its extensive commentarial literature, which includes practice manuals such as the famed Kunzang Lama'i Shelung ("Words of my Perfect Teacher").
These teachings were originally transmitted by the master Padmasambhava to King Trisong Deutsen, the Dakini Yeshe Tsogyal and the Lotsawa ("translator") Vairotsana at Samye Monastery in central Tibet.
The texts that were revealed by Jigme Lingpa, in their present-day form, comprise three volumes, known as the Nyingthig Tsapod (Wylie: snying thig rtsa pod).
The numerous treatises, sadhanas and prayers it contains deal primarily with tantric practice, in particular the 'stages of Development' (Wylie: bskyed-rim) and Dzogchen.
In Finding Ease in Meditation (bsam gtan ngal gso), Longchenpa outlines three main categories of preliminary practices.
[citation needed] There is also a recent English transliteration of Drukpa Kargyud Ngondro written by HH Shakya Rinchen, the 9th Jey Khenpo of Bhutan, titled "The Chariot of Liberation to the Vajra Abode" with detailed footnote and important commentaries by HH Jey Tenzin Dondup, the 69th Supreme Lord Abbot of Bhutan.