Kabbalah s a systematic overview of how existence functions, on every level, from the microcosmic to the macrocosmic. Kabbalah is the basis of all religions, sciences, philosophies, and arts.
The word Kabbalah comes from the Hebrew language and can be spelled Cabala or Qabala and Kabbalah is not an invention or theory: it is the direct perception (reception) of the truth. When the truth is seen, there is no theory or belief needed. The truth simply is. Yet, the fundamental truth cannot be seen physically, because the fundamental truth is beyond the reach of the physical senses.
In the West, the Kabbalah utilizes a primary symbol called the Tree of Life, which illustrates the organizing principle found in every mystical tradition.