The previous article – Introduction to Islamic Sciences, Part I – presented some of the most important Islamic sciences that have long been studied in Islamic seminaries, namely theology (kalam), philosophy, mysticism (irfan), and jurisprudence. 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. Its major subjects comprise of acts of worship, contracts, occasions, and rulings, while its sources include the Qur’an, Sunnah, consensus, and reason. Connected with fiqh is the study of Uṣūl of Fiqh (Principles of Fiqh), or the study of rules used in deducing Islamic laws. This will be studied with a brief look into its history and key issues.