Anuyoga (Skt. 'further yoga') is the designation of the second of the three Inner Tantras according to the ninefold division of practice used by the Nyingma school of Tibetan Buddhism. Yana is a Sanskrit word with a range of meanings including nouns such as vehicle, journey, and path; and verbs such as going, moving, riding, and marching. ... The Nyingma tradition is the oldest of the four major schools of Tibetan Buddhism (the other three being the Kagyu, Sakya and Gelug). ...
As with the other yanas, Anuyoga represents both a scriptural division as well as a specific emphasis of both view and practice. Anuyoga is said to emphasize the completion stage of Tantra, where the preceding division, Mahayoga emphasizes the generation stage.
The Bdud rtsi bam po brgyad pa, composed by Vimalamitra in the eighth century as a commentary to the Bdud rtsi rol pa'i rgyud, is an early example of Tantric works in Tibet which combined sadhana, magic and esoteric scientific procedures.
Vimala had introduced the principal tradition of Rdzogs-chen practice into Tibet, so that the Bam po brgyad pa and Rol pa'i rgyud are also representatives of the Lun Anuyoga stage within that yoga.
In contrast to the 'Padmaist' materials Vimala is only the transmitter of these traditions; their Tantric instruction is their essential function.