translates as Invocation

Name for the pre-Buddhist religious tradition of the Tibetan Himalayas, especially Zhang Zhung, many teachings of which were finally absorbed into Vajrayana.
Practitioners of Bön are called Bön-po.

Bön, previously believed to be a purely shamanic system of belief as has been found elsewhere, more and more scholars have begun to agree with a hitherto controversial theory that early Bön was a combination of Himalayan shamanism and early Buddhist Tantra (before the arrival of Padmasambhava) and elements of Mithraism arriving there from 5th century Persia; along the silk route. As this is not the place to discuss this in datail, I refer the reader to chapter 2 of June Campbell's very clear discussion in her Traveller in Space.

But Bön's independent existence was not to last long. Only a few centuries later, the hitherto not highly organized Bön-po quickly lost ground, and believers, when Indian Tantric masters such as Indrabhuti and Padmasambhava began teaching in Tibet during the 7th and 8th centuries. Philosophically nor politically were they able to withstand the intellectual sophistication and increasing dominance of the Buddhists. It took not long, and Buddhism had risen to the position of state-religion by 779.

By the late 8th century, a movement known as Reformed Bön had evolved which claimed as its founder the Master Tönpa Shenrab, an early, third century shaman and priest. This new Bön had borrowed heavily from the Nyingmapa and was now able to compete with the organized Buddhist schools and sects; having evolved a mythic-historical lineage and written teachings. After the philosophical debate and magical competition in 792, allegedly won by the Vajrayana adepts, the original and unreformed 'Swastika Bön-po' were banned from Tibet and the reformed Bön was grudgingly accepted, by force of Padmasambhava's decree, and allowed to operate in Tibet.

In the centuries to follow, Bön developed alongside the Nyingma and sometimes their teachings were almost similar, each influencing the other. One of the major texts of Tibetan Buddhism, the Bardo Thödol, is strongly influenced by Bön and may even be of Bön origin with Buddhist overlays. By the 11th century, this new Bön had gained some ground and its teachings have been transmitted ever since, on a small scale, into the present time at which it is gaining much interest in the West.

Since the late 1980s, Bön-teachers are also traveling throughout Europe and the United States in order to make their cultural and spiritual heritage, now once more threatened with extinction by the Chinese occupation of Tibet, accessible to others. Also the Tibetan teacher Namkhai Norbu, operating in the West, is one of the few to carry on some of these teachings, especially the Bön mode of Dzogchen.

The approximate date for a first Bön monastery (gYas-ru dben-sa, founded by Yungdrun Lama (gYung-drung bla-ma), is the year 1080.

See here for a specialized bibliography