Künkhyen Pema Karpo (Tib. ཀུན་མཁྱེན་པདྨ་དཀར་པོ་, Wyl. kun mkhyen pad+ma dkar po) aka Ngawang Norbu (Tib. ངག་དབང་ནོར་བུ་, Wyl. ngag dbang nor bu) (1527-1592) was the fourth Gyalwang Drukpa. He was a great scholar and accomplished master of the Drukpa Kagyü school. Gene Smith writes, "The breadth of his scholarship and learning invites comparison with the Fifth Dalai Lama. It was he who systematized the teaching of the Drukpa sect." 
He composed 24 volumes of writings including a history of Buddhism, a commentary on the Bodhicharyavatara, and an in-depth study of the Four yogas, Tib. rnal 'byor bzhi'i nges pa rab tu dbye pa phyag rgya chen po'i bshad pa thams cad kyi bla ma
- Notes on Mahamudra ( རྣལ་འབྱོར་བཞིའི་ངེས་པ་རབ་ཏུ་དབྱེ་བ་ཕྱག་རྒྱ་ཆེན་པོའི་བཤད་པ་ཐམས་ཅད་ཀྱི་བླ་མའོ།)
- The Six Cycles of Equal Taste in a Nutshell
- Distinguishing the Four Yogas with Certainty
- Pointing Out the Sublime Essential Meaning (rnal 'byor bzhi'i bshad pa don dam mdzub tshugs su bstan pa
There were two immediate incarnations of Künkhyen Pema Karpo: Paksam Wangpo who stayed in Tibet and Shabdrung Ngawang Namgyal (1594-1651) who went to Bhutan in 1616, where he introduced the Drukpa Kagyü teachings.
- Among Tibetan Texts, p.82
- see Herbert V. Guenther: Meditation Differently, Padma Dkar-po's 'Definitive Investigation of the Four Tuning-in Phases', Delhi 1992.
- E. Gene Smith, 'Padma dkar po and His History of Buddhism' in Among Tibetan Texts, Boston: Wisdom, 2001
- Michael Broido, 'Padma Dkar-po on Tantra as Ground, Path and Goal' in The Journal of the Tibet Society, Volume 4, 1984
- Michael Broido, 'Padma Dkar-po on Intergration as Ground, Path and Goal' in The Journal of the Tibet Society, Volume 5, 1985
- Michael Broido, 'Padma Dkar-po on the Two Sātyas' in Journal of the International Association of Buddhist Studies 8.2, 1985
- Padma Karpo Ngawang Norbu, The Practice of the Co-Emergent Mahamudra, translated by Ven. Anzan Hoshin sensei, Ottawa: Great Matter Publications, 1991