Tulku Pema Rigtsal Rinpoche is the head of the upper Dudjom lineage known as Namkha Khyung Dzong, formerly based at Mount Kailash in Tibet, of the Ancient order of the Nyingma. Rinpoche reconstructed its primary monastery in exile in Humla, Nepal, where he guides the monastic and ngakpa householder communities. Both a yogi and a scholar, he’s written a number of texts in Tibetan, one of which has been translated into English as The Great Secret of Mind. Here is some more bio info https://www.namkhyung.org/ven-pema-rigtsal-rinpoche/ And https://www.rigpawiki.org/index.php?title=Tulku_Pema_Rigtsal