Illumination or knowledge through light is a central theme of medieval philosophy, especially in the Islamic tradition. This special kind of knowledge finds its source in the Qur´anic Verse of Light. Light became a major theme ofSufism and Islamic philosophy, the former being more closely to the Qur´anic source and the latter standing in the field of philosophy. In his Mishkāt alanwār, the Niche of Lights, Abu Hamid al-Ghazali attempts to expose themeaning of light and knowledge through light. The bridging figure of the “Proof of Islam” opens an original perspective on the matter: through combination of theory and through embedding the knowledge in Sufi practices. Ghazali´s perspective centers on the character of knowledge accessible through illumination that ultimately leads to an awareness of transcendence.