This text is one of the most mysterious and the longest of all the Upanishads. Its name translates as "Esoteric Teachings Shared in the Forest". This ancient Vedic scripture arose as an oral teaching with its earliest passages going back the conversations and discourses of Rishis in about 800 BC or even earlier, in Northern India. It is a thought world that has strange overlaps with the Celtic Druid traditions active in Europe at exactly the same time and some passage in this Upanishads could equally be found in ancient Druid poetry. A similar veneration for the Cosmic Powers is found in both cultures, for instance. So is the love of fire, earth, water and air and the sacred element of Spirit. The Upanishad teaches us that all things come from Spirit and return to Spirit (Brahman) and that the sage understands how to locate the Spirit within ourselves, within our own consciousness. Lives come and go, social status comes and goes, power, money, status, weapons, all those outer things come and go like waves on a lake – but only Dharma, Truth and Spirit remain. This Upanishad is one of the great spiritual teachings of all ages and deserves to be better known. In this Commentary Dr Thomas Daffern, Rector of the Global Green University, brings to bear a life time of studying both the Upanishads and all other world spiritual scriptures. He brings the text alive for spiritual seekers in the complexity of today’s modern world and all its many problems, not least the 2020 Covid 19 crisis and the threat of death many of us are facing, and the existential anxiety this causes. By returning to our inner knowledge of Spirit, which demands only justice and truth as adornments, the Upanishad explains, all things will be well once more.