Dzogchen (“Great Perfection”) is a philosophical and yogic tradition largely developed within the Bönpo tradition of Tibetan Buddhism. Its first datable sources surface on the religious scene of Tibet sometime around the late 10th to the early 11th century with the discoveries of Treasure text (gter ma) that are supposed to have been hidden during the 8th century and earlier, as well as with the seminal composition of texts and commentaries that are based on these Treasures. Some of its teachings are also presented as having been transmitted orally from archaic, undatable times through an uninterrupted lineage of masters. Groups of lay Bönpo practitioners, later followed by monastics of the same tradition, started to gather around the discoverers and authors of these works, thus creating the first postdynastic religious communities of Bön dispersed throughout Tibet. Deeply enriched by the integration of a vast amount of traditional Buddhist literature, the Bön tradition absorbed teachings from all other Tibetan Buddhist lineages. The core of these teachings is made up of profoundly secret instructions said to enable practitioners to reach the state of total Buddhahood in a single lifetime. The quintessence of these teachings focuses upon yogic techniques centered on the contemplation of light sources, such as the sun, the moon, or a butter lamp. Particular methods are also applied in a completely dark room in which special visualizations are combined with yogic devices that lead to visionary experiences which are unique throughout Buddhist teachings. These practices based on colored visions produce various signs manifesting at the end of the practitioner’s life such as the famed Rainbow Body (‘ja’ lus).