Bön traces its founder to Tonpa Shenrab of Zhang Zhung, its teachings organized in the Nine Ways of Bön and preserved in its own canon, the Kangyur and Katen, printed in the 18th century. Western scholarship distinguishes an older stratum of pre-Buddhist ritual from the organized Yungdrung Bön documented from around the 10th-11th centuries. Samten Karmay's studies, The Arrow and the Spindle (1998) among them, are the standard academic sources.
Popular accounts treat Bön as Tibet's pure pre-Buddhist shamanism, a claim the tradition's own texts complicate: organized Bön has monasteries, philosophy, and a Dzogchen of its own. The 'shamanic Bön' of Western books is partly a projection of what Tibet was supposed to be.
Bön's name for itself, Yungdrung, 'eternal swastika', the unborn and indestructible, claims the doctrine is not a religion among religions but the timeless pattern they interrupt. Its counterclockwise swastika marks the whole tradition as Buddhism's inversion twin.
If two rival traditions become mirror images, which one is the reflection?