In the eastern edges of the
Arabian Peninsula there were cities dedicated to scholarship and learning. Not exactly like Western Universities, but more than close enough for comparison. When
Wahabism formed in the early 18th century
the founder decided these scholars were "innovators" and anti-Islamic. So his followers attacked and burned these cities.
Many of Homeline's scholars see that as a vast tragedy. The libraries of these cities were supposed to have vast numbers of ancient books from as far afield as Spain, Greece, Iran, India, China and even Japan. The burning of these cities was probably a loss at least equal to the burning of the Library of Alexandria or worse.
Basically, the PCs are to go to exotic desert cities in a troubled land and get copies of books that violent fanatics think are the tools of Satan.