This work is the first comprehensive study in the German language that systematically addresses Sunni Islamic legal methodology and the theory of legal sources. The author aims to elucidate the normative system connections and characteristics of Islamic legal source theories as they are typically presented for Arabic-speaking Muslim authors and audiences today, even though they belong to different legal systems in practice. While Islamic law should not be confused with the law of Islamic states, Sharia serves as the starting point, foundation, and benchmark for assessment in Islamic countries and many Arab states. As such, it also claims future validity. The author reconstructs the development of Islamic law from its beginnings to the present. She follows the E.