Systema Sephirotica

Ten sephirot of nothingness : Their measure is ten which have no end. A depth of beginning, a depth of end ...

Qaballah (or Kabbalah, Cabala, choose your flavor) means "tradition". Rabbi Akhiba and his pupil Simon Ben Jochai summarized the magical practice and knowledge of the elder in the 1st century A.C.
Originally it was a science of understanding/interpretation of god, the divine work, creation of man. But as Qaballah is rather old, many of it's doctrines are considered "false" by nowadays Christian church. Some thought that studying Qaballah would give power over the elements (alchemy, magic), and this fact supports the condemning of Qaballah by the Catholic church since then (A prominent figure to name would be Alistair Crowley).
Nonetheless Qaballah represents an interesting concept of god's creation, as it is distinguished by its theory of ten creative forces that intervene between the infinite, unknowable God ("Ein Sof") and our world. Through these powers God created and rules the universe.
This ten "forces" or incarnations of god can be displayed in the so called Systema Sephirotica, also known as Tree of Life. The left side of this tree features the feminine principles of separation and distinction, the right side has the masculine principles of unity and harmony. (This doesn't per sé mean a person identified with a certain sephira has to be of the according gender !)