The Book of Rulerships:

First and foremost, this is a reference book on rulerships; second, this is a classical concordance. Although astrological works dating from the seventeenth century and earlier lack explanations or discussions of the methods of assigning rulerships, we know that rulerships were assigned, and continue to be assigned, right up to the present moment, as new concepts/things are invented/discovered. Dr. Lehman examines how this process was really practiced in the classical period to give us insights into how to proceed today.