http://www.junginla.org/t/bookstore/bookstore-treasures/audio-cds/p/conception-of-tselem-the-astral-body-in-jewish-mysticism
http://www.amazon.com/On-Mystical-Shape-Godhead-Mysticism/dp/0805210814
In this lecture the preeminent scholar in Jewish mysticism Gershom Scholem speaks of the Kabbalistic doctrine of the tselem, the astral body. The word "tselem" first appears in Genesis 1:26 when God creates man and says “let us make man in our image (tselem) and in our likeness.” In Hebrew "tselem" means "plastic image" and describes the individual essence of each human being. It constitutes an independent entity mediating between body and spirit. In mystical experience, the tselem could manifest as the perception of one’s own double, which revealed the deepest spiritual essence within man. Professor Scholem retraces the historical development of the doctrine of the tselem in Jewish mysticism and tells us how it is related to the principle of individuation in man.

Quotation from "Shoshan Sodot":
"The deeply learned Rabbi Nathan, of blessed memory, said to me: Know that the complete secret of prophecy to a prophet consists in that he suddenly sees the form of his self standing before him, and he forgets his own self and ignores it...and that form speaks with him and tells him the future. And concerning this our sages said.'Great is the power of the prophets, who make the form [appearing to them] to resemble its Former.' And the learned sage Rabbi Abraham ibn Ezra, of blessed memory, said: 'The one who hears [at the time of prophecy] is a human being, and the one who speaks is a human being.' And another learned man wrote the following: 'It occurred to me, by the power of combination [of letters of the holy names of God] and by solitary meditation, that I encountered that light which accompanied me, as I have discussed in the book 'Sha'arei Tsedek'. But to see my own form standing before me - this I was not granted and this I cannot bring about.' Yet another learned man writes the following: 'And I, the young one, know and acknowledge with full certainty that I am not a prophet nor the son of a prophet, and I have not the holy spirit and I do not make use of the heavenly voice ; these things have not been vouchsafed to me, and I have not taken off my garment or washed my feet. Nevertheless, I call on heaven and earth to witness - as the heavens are my witness and my Guarantor is on high! - that one day I was sitting and writing down a Kabbalistic secret, when suddenly I saw the form of my self standing before me, and my own self disappeared from me, and I was forced and compelled to cease writing.' "