The Gate of Ivory — Doris Egan

THE SCIENCE OF MAGIC--
is what lures people from all over the galaxy to the world of Ivory. Ivory, exotic and dangerous, where everything is for sale, and law exists only to protect the most powerful families. And to anthropology student Theodora of Pyrene, Ivory--the one place in the known universe where magic works and where those who command it can control society--is an irresistible world to explore on her all-too-brief vacation.

But cut off from her companions and her ship, attacked and robbed. Theodora's short pleasure trip soon becomes a terrifying odyssey. For on Ivory all her studies and training are useless, and Theodora is forced to turn to fortune telling to survive. To her amazement, she discovers that she actually is gifted with magical skill, a skill that will plunge her into deadly peril, when she becomes involved with Ran Cormallon, one of the most powerful sorcerers on Ivory--and a man whose unknown enemies will stop at nothing, including spell-murdering Theodora, in their campaign to destroy Ran and seize his power!