Kabbalah

"Kabbalah is an aspect of Jewish mysticism. It consists of a large body of speculation on the nature of divinity, the creation, the origin and fate of the soul, and the role of human beings. It consists also of meditative, devotional, mystical and magical practices which were taught only to a select few and for this reason Kabbalah is regarded as an esoteric offshoot of Judaism. Some aspects of Kabbalah have been studied and used by non-Jews for several hundred years (Hermetic Kabbalah)."

Literally, "The Personally received teaching".

That is, a teaching not derived from books or doctrine, or even oral traditions, but one directly experienced.

So this then, is the science of exploring the inner world. We all have our (subjective) interpretation of reality.

It, as a coined term, and an "organized" science, dates back to the 1st century or so, though, perhaps much earlier. It possibly has Egyptian influences, and almost certianly Greek touches.

A primary focus of any "study" of Kaballah is

Alternative spellings: Cabala, Qaballah.

Check out William Gray's book "The Ladder of Lights" for a good introduction.