Previously I have posted links to museums that provide free access to their publications as in web and downloadable PDF versions. I encourage you to take advantage of these ebooks; they feature excellent essays, high resolution images, and informational captions. There you will also find bibliographic information for further research.
Here are three links to facilitate your searches among the 400+ free titles:
Islamic Art in the Early Period
Islamic Art in the Medieval Period
Islamic Art in the Later Period
Art History Resources 