GURPS is a well known book and is actually a collection of short alternative history stories.
Caliph by Hite, Kenneth, Craig Neumeier, and Michael Schiffer
Published in GURPS Alternate Earths II
In OTL the knowledge of paper making arrived in the Islamic world in 749 after the historic battle of Talas river when some Chinese were captured who helped the Muslim Caliph to construct a paper making factory in present day Iraq. In this story the knowledge of printing arrives in the Islamic world from China. Haroun al-Rashid became the patron of a printing press in Baghdad in 796. Due to widespread availability of knowledge to a large segment of population as a consequence of printing the scientific revolution starts in the 9th century. 800 years later the interplanetary Dar al-Islam is thrown into a terrifying war.