Usul fiqh refers to the methodology and principles used to derive rulings from Islamic legal sources like the Quran and hadith. It examines topics like different types of legal rulings and their objectives. There are two main types of rulings - taklifi which define obligations and prohibitions, and wadh'i which regulate the implementation of taklifi rulings. Taklifi rulings include obligatory, recommended, permissible, improper and prohibited acts. Wadh'i rulings specify elements like causes, conditions and obstacles related to legal rulings. Scholars from different Islamic legal schools like Hanafi and Shafii have approached usul fiqh differently in areas like scope and practical application.