What is Dzogchen?
Dzogchen, or Dzogpa Chenpo, is the Tibetan name for a set of teachings known in English as the Great Perfection. Within the Tibetan Buddhist tradition these ancient and secret teachings are the most exalted and profound of all the secret tantras. The supreme goal of practice is enlightenment or Buddhahood, which can be attained in a single lifetime. Through concentrated practice many extraordinary qualities can be achieved, including unobstructed clairvoyance and the ability to sustain oneself without need for food or shelter. Someone who masters these teachings will have control over their life span and when they do pass away their physical elements will be liberated into the rainbow body. It was dedication to the practice of the Great Perfection which led to both the monastery and the entire district becoming known as Dzogchen.
These profound teachings originated with the primordial Buddha Samantabhadra, and were brought to Tibet by the great tantric master Guru Rinpoche / Padmasambhava in the 9th century. Since then, the teachings have been passed down secretly by masters to a few select students. The holy lineage of the Great Perfection is maintained to this day in Dzogchen Monastery.
For a detailed explanation of the Dzogchen tradition read Words of My Perfect Teacher by Patrul Rinpoche. This book was written in Dzogchen Monastery and explains clearly how to practise Tibetan Buddhism in the Dzogchen tradition.