The whole card emits a quietly controlled power which suggests something may manifest at any moment. This is the Great Isis, in her own right a magician of unutterable power. As the Moon Priestess she is change, hidden knowledge, psychism and the magical powers of life. Her magnificent eyes hold promise ... but of what?The High Priestess is the card of knowledge, instinctual, supernatural, secret knowledge. She holds scrolls of arcane information that she might, or might not reveal to you. The moon crown on her head as well as the crescent by her foot indicates her willingness to illuminate what you otherwise might not see, reveal the secrets you need to know in order to make a decision about a problem or a job, an investment, love, career, family, etc.
And, finally, there is, behind her throne, the curtain that leads to the deepest, most esoteric and secret knowledge; she is perhaps Persephone, who was taken down into the land of the dead, ate its fruit, and became the only goddess allowed to travel to and from that strange land. Which indicates that when you get the High Priestess, you're going to be learning some very odd things. Very odd.
Standing for someone other than the Querent, the High Priestess is usually read as a spiritual woman, a nun or astrologer, a teacher of archaic knowledge, or just a reclusive relative who knows a lot of family secrets. She is a repository of obscure knowledge, a walking library with uncanny instincts and insights. She may, as well, come across as cold, unpredictable, even scary.
As a card, the High Priestess is about knowledge. Insider knowledge. The more secrets the querent knows, the easier it is to know what to do with the idea. This is the job of the High Priestess, to offer secret knowledge, like the moon on a dark night, so that the querent can find their path. She sits between the pillars of dark and light, existence and negation, wax and wane. All secret knowledge is hers.