Career
He was the son of a famous talmudist Abraham ben David of Posquières (Raavad). The Bahir first appeared in the Middle Ages, around 1200 Civil Engineering in France. The most influential of these was Isaac the Blind.
He considered the sefirot as having their origins in a hidden and infinite level deep within the Ayn Sof, or Divine Being (lit That Without End).
He believed that from the Ayn Sof emanated Makhshava (Divine Thought), which was the first supernatural quality. The rest of the sefirot emanated from the Divine Thought.
Individual beings in the world are material manifestation of the sefirot, albeit on a lower level of reality. Mystic experience aids in reascending the levels of emanations to unite with Divine Thought.
The most famous student of Isaac the Blind was Azriel.