Pranava is known as the word of power in Hindu philosophy as it is thought to be the primordial sound from which the universe originated. It is the most sacred of all mantras and syllables because it causes all prana to unite with the Divine. Om can be thought of as the sound of God.
Performing Pranava yoga has a profound effect on the mind and spirit because it helps the yogi reach more subtle levels of awareness, where they may rediscover their unity with the Divine. Some consider it a tool to shape consciousness itself.
To understand our connection with the universe is to know our true selves, free from illusion. That is the essence of pranava.