Jñānasūtra (Tib. ཡེ་ཤེས་མདོ་, Wyl. ye shes mdo) — one of the early masters of the Dzogchen lineage. He was a disciple of Shri Singha and the main teacher of Vimalamitra. His last testament, which he conferred upon Vimalamitra before passing into the rainbow body, is called the Four Means of Abiding.