Western society has depreciated the Middle Ages as the ‘Darkness’. However, if Islam, which led the medieval millennium, had not spread paper and art of papermaking, and Arabic translations to the Western countries, translating and interpreting Arabic manuscripts into Greek and Latin, Gutenberg's printing press, Reformation, and Renaissance could not take place. They were not destructors of ancient knowledge and civilization, but were the protagonists of restoration and resurrection. The base camp is the Mosque and Islamic library(the House of Wisdom), which was referred to as a Muslim community. This study traced Islamic libraries that emerged in the process of establishing the Islamic dynasties and controlling Arabian Peninsula, Africa, Iberian Peninsula. For this purpose, the Islamic library was divided into the caliph library led by the royal families, the public library attached to the mosques, and the private library established by the viziers and scholars, etc. Then, the researcher analyzed history and development, roles and functions, impact and Importance on human civilization, and stagnation and decline, focusing on major libraries that existed in the Islamic cities of Damascus, Mecca, Baghdad, Aleppo, Cordoba, Cairo, Fes, Tunis, etc.