Kabalah (Cabala, Qabalah) is an ancient Hebrew method that investigates man's position in the universe.
Qabalah in its name means 'mystery'. It is a general term, where the tree of life is the primary model that connects the human being with the universe. In this system the human being is a little universe. There are basic philosophies of Qabalah, and some of them are more popular than others. None of them is Qabalah on its own though. The oldest text of Qabalah is the Sepher Yetzirah or Book of Formation (traditionally considered to describe how the world is formed out of Hebrew letter principles).
The Sepher Yetzirah describes a tree of life in three dimensions like a sphere or cube or double-pyramid around a soul center. Later Qabalistic philosophers took the same tend spheres or principles of the Sepher Yetzirah and organized them one on top of the other in two dimensions like a tree, and called it the tree of life from the one mentioned in Eden in the bible. The Sepher Yetzirah has many versions of altered texts, and nobody knows what the original was. It was probably written around the time of Christ, but the oldest copy we have came a thousand years later.
The original Hebrew spelling is QBLH (I'm usuing latin letter equivalents for Qof.Bayt.Lammed.Heh). Each letter is a magical concept and a divine one in this system. The different spellings of the word are just some of the many adaptations and versions. There were many philosophical extensions building on the principles of the Sepher Yetzirah, but these also evolved with Jewish dogma, which underwent some changes over the last 2000 years after the fall of Jerusalem (twice) in the first and second centuries ACE.
The Sepher Bahir, Zohar and other works are part of this tradition.
The Tree of Life has many associations attached to it and I will trey to explain the best that I can.
The Tree and the associations attached to includes placing the various Divine Names, planets, Archangels, Angels, and metals in a logical order so that we as magicians can understand the universe around us.
One of the best explanations is given by noted author Dion Fortune and is respected through the world of Magick,
The Tree of Life is a composite of symbols, which are intended to represent the cosmos in its entirety and the soul of man as it relates thereto; and the more we study it, the more we see that it is an amazingly adequate representation; we use it as an engineer or the mathematician uses his slide-rule, to scan and calculate the intricacies of existence, visible and invisible, in external nature or the hidden depth of the soul ( from the Mystical Qabbalah )
The Tree of Life and it's 22 paths relates to as well as works with the 22 Major Arcana cards of the tarot and the Ten Divine Emanations, called the sephiroth (plural of the word sephira), and the lines symbolize Paths that connect the individual sephira to one another.
The ten spheres or Sephiroth connected by the 22 paths of the Hebrew alphabet, form the The Tree of Life describes the steps between mundane consciousness (represented by Malkuth) and the divine (represented by Kether).
The following is the basic information on The Tree of Life
The various names of the sephiroth are derived from Scripture. The first three of the sephiroth are named in Exodus 31:3:
and I have filled him with the Spirit of God, with skill, ability and knowledge in all kinds of crafts ( the Bible )
''spirit of God'' refers to Kether, while ''Wisdom'' and ''Understanding'' refer to the next two sephiroth, Chokmah and Binah, as well as the hidden sephira Daath that follows these two sephiroth.The next seven sephiroth on the Tree of Life have their names derived from 1 Chronicles 29:11:
For more info look through these sites:
The site above has a links page with many topics on Qabalah and the Sepher Yetzirah as well as other esoteric themes: