This article touches upon two subjects: Fiqh (Islamic Jurisprudence) and Usul of Fiqh (Principles of Fiqh). Fiqh - the profound understanding of religious rulings - is the most comprehensive subject in Islamic sciences. Among the five schools of thought, namely, Ja’fari, Hanafi, Hanbali, Shafi’i, and Maliki, this article delves into Shi‘a Ja’fari fiqh, offering a glance into its history, key subjects, and sources.