Eight Upanishads: Volume 1 & 2 (PocketBook)

Beyond all sound all sight, beyond form, absolute, beyond all taste and touch, infinite, without beginning and without end, even beyond nature, the unchangeable – he who realises Him, frees himself from the jaws of death. But it is very difficult. It is, as it were, walking on the edge of a razor, the way is long and perilous, but struggle on, do not despair. Awake, arise, and stop not till the goal is reached. The one central idea throughout the all the Upanishads is that of realizations

-     Swami Vivekananda.