point of view, its contents, if put into practice, enable the astrologer to achieve a bet-
ter than 80 percent accuracy. It thereby calls into question the doctrine of free will as
it is held by religionists and by secular humanists. Philosophically, Liber astronomicus
demands that the philosopher reexamine the conclusions of the Jewish and Arabic
neoplatonists—Al-Fa ̄ra ̄bı ̄, Ibn Sı ̄na ̄, ibn Gabirol, and Ibn Rushd. From the point of
view of the practice of the art, it ought to be recognized that astrology in medieval
Islam was and continues to be regarded as a traditional and sacred science subordinate
only to the Koran. It was as such that astrology reentered western Europe in the
twelfth century.
The Liber astronomicusallows for the recovery of much of what was ill-advised-
ly tossed out as “superstition,” “Arabic” (i.e., allegedly corrupt), and “papist.”—Robert ZollerSources:
Debus, Allen G. World Who’s Who in Science.1st ed. Chicago: Marquis’ Who’s Who, 1968.
Halliwell-Phillipps, J. P., ed. The Private Library of Dr. John Dee, and the Catalogue of his Library
of Manuscripts.London: Camden Society Publications, 1842.
James, Montague R. Lists of Manuscripts Formerly Owned by Dr. John Dee.Oxford: Bibliographi-
cal Society, 1921.
Kibre, Pearl. The Library of Pico Della Mirandola.New York: Columbia University Press, 1969.
Liber Astronomiae.Appeared in print in Latin first in 1491 at Augsburg. Radolt was the publish-
er (G.W. 4643). Other Latin editions were produced in Venice (1506), and Basel (1530
and 1550).
Thorndike, Lynn. History of Magic and Experimental Science, Vol. II.New York: Columbia Uni-
versity Press, 1923.
Zoller, Robert. “The Astrologer as Military Adviser in the Middle Ages,” Astrology Quarterly.
(1992–93).BOOMERANG
A boomerang is a configuration resembling a yod but involving a fourth planet direct-
ly opposed to the “action planet” at the tip of the yod. In a yod, two planets form a
sextile (60°) aspect and both in turn form a quincunx (150°) aspect with a third plan-
et. If lines were drawn to the center of the horoscope from all three planets, the result-
ing pattern would look like a capital Y. The planet at the bottom tip of the Y is said to
be the action planet because its house placement is where the action takes place when
the configuration is activated by a transit or a progression. The interpretation often
given to a yod in a natal chart is that it indicates a life that proceeds along in a certain
pattern for a period of time until the established pattern is abruptly interrupted and
the native is forced to proceed in a new direction, though the new direction is one for
which the person had actually been preparing for some time. A completely unantici-
pated promotion in one’s chosen profession, for example, might be brought about by
an activated yod configuration.
When a fourth planet is involved in a yod so that it forms an opposition
(180°) aspect to the action planet and semisextile (30°) aspects to the remaining two
planets, the resulting formation is called a boomerang, a designation coined by JoanBoomerang
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