I was introduced to Tiisi: and his Tadhkira some 19 years ago. That
first meeting was neither happy nor auspicious. My graduate student
notes from the time indicate a certain level of confusion and
frustration; I seem to have had trouble with such words as tadwlr
(epicycle), which was not to be found in my standard dictionary, and
with the concept of solid-sphere astronomy, which, when found, was
pooh-poohed in the standard sources. I had another, even more decisive
reaction: boredom. Only the end of the term brought relief, and I was
grateful to be on to other, more exciting aspects of the history of
science. A few years later, I found myself, thanks to fellowships from
Fulbright-Hays and the American Research Center in Egypt, happily
immersed in the manu- script collections of Damascus, Aleppo, and Cairo.
Though I had intended to work on a topic in the history of mathematics,
I was drawn, perhaps inevitably, to a certain type of astronomical
writing falling under the rubric of hay' a. At first this fascination
was based on sheer numbers; that so many medieval scientists could have
written on such a subject must mean something, I told myself. (I was in
a sociological mode at the time.