When we run yoga teacher trainings in Vancouver, we sometimes get asked what are the major books of yoga. One of them is the Upanishads are a group of writings considered to be the continuation of the Vedas. Being written around 800-200BCE, The Upanishads explain the core truth of the Vedas and were kept within the Priest or Brahman class until only recently.
Sometimes referred to as the Vedanta, these texts outline the central monistic and philosophical ideas of Hinduism and Yoga. The teachings in The Upanishads were passed down orally for many centuries before finally being written down and codified.
The word Upanishad translates roughly to “Sitting next to/near” – this probably referred to the ceremonial context wherein the student would receive the oral teachings from his Guru.
There is believed to be 108 Upanishads. The core teaching throughout is that You (all human beings) are Atman; the Soul/Self. This Self exists in the Ultimate Reality/Truth of Brahman.
The mystic or transcendental teachings of the Upanishads are delivered to show beyond doubt that the Atman is inseparable from Brahman; that your “Self” is unified and no different from the Ultimate Truth of the Universe.
This philosophy is expounded dialectically throughout each Upanishad, eliminating common illusions that hold one in suffering piece by piece. Some believe that the reading of these texts alone cannot take one to the heights of Samadhi.
That all other Yoga practices in conjunction must be practiced alongside the reading. They reason that because the human system has many parts, and the Upanishadic philosophies serve to correct one aspect; namely misidentification of the self with the body, thoughts, emotions, etc.
With that being said there is one path of Yoga that focuses exclusively on the attainment of wisdom, that is Jnana Yoga. Jnana Yogis will study The Vedas, The Upanishads, and many other texts their whole lives in order to attain perfect Enlightenment.
Whether or not these texts are the only way to Enlightenment is a matter of opinion, what we do know is that they contain the ancient wisdom of the Yogis!