The full name is The Kabalistic Sephiroth,and is often called the Tree of Life. It is to be regarded as symbolic of the Microcosm (man) and The Cosmos. It is very ancient and as with all such wisdom, was transmitted in oral fashion for thousands of years, the recorded version being of Judaic origin.The history is best found in the Encyclopaedia Brittanica.
An illustration shows ten circles numbered from 1 to 10 in descending order*, these are the "Sephira"and are intended to represent the formation of The Creation, the Three Supernals at the top of The Tree are The Trinity and are abstract. The Manifestation of the created is in the numbered sequence from above, down to the lowest which is the physical world. Seven sephira are related to planets, as shown on the diagram, the uppermost (Kether) is The Absolute followed by Binah as the primordial chaos, and Chokmah as the Zodiac, the three representing The Abstraction from which All is created.
The Right and the Left Columns are of positive and negative polarity identical with the idea of Yin and Yang. The Middle Column is the path of the Kundalini Power at the base of the spine, and when the Tree is super-imposed on the the human frame and the various sephira are placed on the shoulders, hips and knees in the judaic texts, together with the particular planets and their astrological symbols.
Together with the 22 paths joining them and the 10 sephira are formed the 32 paths of The Sephira Yetztira or" Book of Formation ". The lines connecting the sephira from below upwards represent the grades of iniation in the mystery schools ,some of them have reduced the number required,one of the most ancient to only three degrees. Each sephira has a colour thought most appropriate to its heavenly symbol, and in the same way so has each connecting line (or path). These colours are different according to which of "The Four Kingdoms"are represented.
The Caduceus of Mercury is twin serpents coiled three-times around the sephira and the heads separated at the upper three facing outwards and has been adopted world-wide as emblem of the medical profession.What is not generally known, is that contemplation of The Tree of Life inspired the notion that the pituitary gland was the controller of the endocrine system.
Regarding contemplation of The Tree of Life it is possible to imagine the sephira imposed on the physical frame and is called "The Way of The Middle Pillar" as a kind of Yoga. It is fully described in the book by Israel Regardie .
An explanation of what appears to be an 11th. sephira on the Tree is in reference to a temporary psychic centre situated between the shoulders at the base of the neckcreated during yogic development, called "Daath"(or Daas), and usually shown in dotted lines as it is not part of the Tree.
From Chesed and Geburah are formed the arms, the fingers are symbols of the Four Elements and Spirit: Thumb(Spirit),3rd.finger (Fire), Index finger (Water), Little finger (Air), Second finger (Earth). In some cultures it is a serious error to point with the index finger, the medicine man of the American Redskins was only permitted to indicate with the thumb . The most important of the sephira is the one named "Tiphareth" and is related to the sun and is the largest psychic centre and The Heart Centre, more of which is to be read in the chapters on Yoga and Soul.