The High Priestess represents wisdom, serenity, knowledge and understanding. She sits in front of the thin veil of awareness, which is all that separates us from our inner selves. The High Priestess knows the secret of how to access these realms. She represents spiritual enlightenment and inner illumination, divine knowledge and wisdom. She has a deep, intuitive understanding of the Universe and uses this knowledge to teach rather than to try to control others.
"She walks in beauty, like the night of cloudless climes and starry skies..." I didn't think her beautiful, but when I looked at her, it was the first thing I thought of, Lord Byron's "She Walks in Beauty"