|Notes on the Exhibition:
Two Kabbalistic Series
In 1995, a retrospective exhibit required me to consider and describe in writing the body of twenty-years' painting.  Given the subject matter of my work, I was also forced to reflect upon my concurrent study of Jewish mysticism and Kabbalah, in all of their expressions. 
Realizations about my work were at once illuminating and, for a time, crippling. In various ways, the paintings all depicted one phase or another of a four-stage progression (the clearest expression of which being the series Baw. Daw, Moy. Ding). The four stages were
All twenty-eight of the paintings selected for the 1995 show fell so naturally into these categories that each was classified A, B, C, or D to indicate which stage it represented.
Finding this only-too-easy catagorization scheme for my work. along with preparing the show more generally, left me with the feeling that I was curating a posthumous show.
After about a year or so away from painting kabbalistic themes, the time came to re-evaluate where I had been in order to figure out where I might go. Correspondence (or analogy) to the kabbalistic tree of life provided an inroad. Loaded into the symbolism and concepts of the four-stage system was the underlying notion that it represented progress up the middle pillar, namely
D. some contact with the supernal realm
What I had not yet done was depict the supernals, namely binah, hokhmah, and keter. The formulae for the Rosicrucian grades corresponding to the highest sefirot provided a place to start:
binah . . . 8 = 3 . . . Magister Templi . . . Joy Is Sorrow
hokhmah. . .9 = 2 . . . Magus . . . Change Is Stability
keter . . .10 = 1 . . .Ipsissimus . . .Self is Selflessness
Variations on these ideas became mixed with sympathetic symbols for the supernal spheres and began to coalesce into images. In the case of 10 = 1, "Self Is Selflessness" translated naturally to "All Is Not (or Nothing)" or "God Is Not,"  which eventually lapsed into 0 = 2, the formula to which I deferred when it became clear that a painting of 10 = 1 was not possible for me.
 Don Karr: A Retrospective Exhibit, at the Lahr Gallery, Haddonfield, New Jersey, May 5th-31st, 1995.
Jewish mysticism includes apocalyptic, merkabah/hekhalot mysticism, German Hasidim, etc. Kabbalah has a complex history including numerous Jewish and Christian developments. See endnote.
The formula "God Is Not" is nuanced by the kabbalistic terms for the most remote aspect of the deity: ayin and en sof. which mean "nothing" or "no thing."
It is impossible to recommend one book to the reader as a suitable introduction to mystical currents in Judaism. The most famous work--by the most famous scholar--is the grand summary Major Trends in Jewish Mysticism by Gershom Scholem (New York: Schocken, 1941)
While certainly a "classic" in the field, this work is a bit thin in some areas, and a number of its conclusions are being debated. Charging Major Trends head on regarding many points is Moshe Idel's Kabbalah: New Perspectives (New Haven: Yale University Press, 1988). Following several key ideas through the whole history of Jewish mysticism is Through a Speculum That Shines, by Elliot R. Wolfson (Princeton: Princeton University Press, 1994).
For closer studies of particular phases of mysticism within Judaism. I recommend the following:
Collins, John J. (1984)The Apocalyptic Imagination: An Introduction to the Jewish Matrix of Christianity. New York: Crossroad.
(2nd edition = The Apocalyptic Imagination: An Introduction to Jewish Apocalyptic Literature Grand Rapids: Wm.B. Eerdmans Publishing Company, 1998.
Dan, Joseph. (1993)The Ancient Jewish Mysticism. Tel-Aviv: MOD Books.
Schaefer, Peter. (1992) The Hidden and Manifest God: Some Major Themes in Early Jewish Mysticism. Albany: State University of New York Press.
Marcus, Ivan G. (1981) Piety and Society: The Jewish Pietists of Medieval Germany. Leiden: E.J. Brill.
Green, Arthur. (1984) "The Zohar: Jewish Mysticism in Medieval Spain," in An Introduction to the Medieval Mystics of Europe. edited by Paul Szarmach. Albany: State University of New York Press. Green 1984 also in Essential Papers on Kabbalah, edited by Lawrence Fine. New York: New York University Press, 1995.
Bar-Lev, Rabbi Yechiel. (1994) Song of the Soul: Introduction to Kabbalah. Petach Tikva: n.p.
For Christian/Western esoteric developments of kabbalah. refer to the following:
Blau. Joseph Leon. (1944)The Christian Interpretation of the Cabala in the Renaissance. New York: Columbia University Press.
My suggestions are intended to get the reader started. These works represent only a minute fraction of a vast and complex literature.