Theos Casimir Hamati Bernard (1908–1947) was an explorer and author, known for his work on yoga and religious studies, particularly in Tibetan Buddhism. He was the nephew of Pierre Arnold Bernard, "Oom the Omnipotent", and like him became a yoga celebrity. His account of old-style hatha yoga as a spiritual path, Hatha Yoga: The Report of A Personal Experience, is a rare insight into the way these practices, known from medieval documents like the Hatha Yoga Pradipika, actually worked.