Kabbalah: The Tree of Life
The Tree of Life describes the descent of the divine into the manifest world, and methods by which divine union may be
attained in this life. It can be viewed as a map of the human psyche and of the workings of creation, both manifest
and unmanifest. Indeed, any system can be more fully understood both in itself and relative to any other system by
viewing it in relation to the Tree of Life. The Tree allows and requires a more holistic understanding of any topic
to which it is applied  reason, spiritual perception and intuition are all needed, as is clear from the structure
of the Tree itself.
It is important to realize that the pure nature of divinity is unity, and that the seemingly separate aspects or emanations exist only in view of the emanated, living in a state of illusory separation. Qabalah could be thought on as the mathematics of the esoteric with the literary side consisting of legends, myths and lore. In Qabalah numbers have a deeper significance. This could be because numbers have mystical properties in themselves, or it could be that numbers, being the purest of symbols, are appropriate entities to hang metaphysical concepts on. It is difficult to imagine, but the originators of Qabalah had a very different number system from the one we are familiar with today. There is a difference between cardinal numbers (how many there are: 1, 2, 3 ...) and ordinal numbers (1st, 2nd, 3rd ...). To represent cardinal numbers the early Semitic people used letters : aleph = 1, beth = 2, ... This is the basis of Gematria, where words also have numerical values. 
The Sephiroth and Paths of Qabalah represent ordinal numbers. And these have a deeper siginificance because Kether, the first emanation of the Divine, really represents the first, the first thing to exist. The number system we use in the west today is suited to modelling our environment and using these models to manipulate matter. The number system of Qabalah is suited to modelling metaphysical concepts and gaining insight. Qabalah could be thought on as the mathematics of the esoteric with the literary side consisting of legends, myths and lore. In Qabalah numbers have a deeper significance. This could be because numbers have mystical properties in themselves, or it could be that numbers, being the purest of symbols, are appropriate entities to hang metaphysical concepts on.
It is difficult to imagine, but the originators of Qabalah had a very different number system from the one we are familiar with today. There is a difference between cardinal numbers (how many there are: 1, 2, 3 ...) and ordinal numbers (1st, 2nd, 3rd ...). To represent cardinal numbers the early Semitic people used letters : aleph = 1, beth = 2, ... This is the basis of Gematria, where words also have numerical values.
The Sephiroth and Paths of Qabalah represent ordinal numbers. (1st, 2nd, 3rd,...) And these have a deeper siginificance because Kether, the first emanation of the Divine, really represents the first, the first thing to exist. The number system we use in the west today is suited to modelling our environment and using these models to manipulate matter. The number system of Qabalah is suited to modelling metaphysical concepts and gaining insight.
Along with the Tarot, we can use different paths in the Tree of Life to reach insights, gain wisdom and finally Enlightenment.
from byzant.com & Merlyn's notes

Sacred Geometry: The Tree of Life in the Flower of Life 
Links Tree of life and the Circuits (10 though? :p) Byzant Kabbalah, Tree of Life and Tarot Kabbalah clip: Kabbalah Codex Tree of life Kabbalah clip: Tree of life Aleister Crowley: Liber 777 Kabbalah Streaming Vids 