Oriental rugs by Janice summers is a quick and easy read and can also be used as a reference for rug ID. Good color photos as well. Definitely worth owning.
The Persian Carpet by Cecil Edwards is a must own as well, super interesting to hear from someone in the rug trade, living, working and traveling through Persia, through the end of the "golden" era for Persian carpets (1910-1950s)
Ellen Amirkhan and Aaron Groseclose's book, A Comprehensive Guide to Oriental & Specialty Rug Cleaning, is great as well definitely worth the price tag. Better yet take the Master Rug Cleaner course and get one included with tuition. Great reference for rug ID.