This course treats al-Qiyas, the Analogy, in an inclusive study in the Science of the Principles of Islamic Jurisprudence, including all the relating details to this subject. Thus, it tackles the concept and scope of both of reasoning and analogy. In addition to this, it sheds light on the following issues. The legitimacy and ‘fundamental constituents’ of analogy. The conditions of the ruling that is derived from the text, and the conditions of ruling of the new case which is likened to the former ruling. Al-‘Illah, cause, and its divisions according to the objectives, interests, or consideration. The divisions and conditions of the cause according to the Hanafi school in particular. Masalik al-‘Illah, the ways by which the cause is derived. Al-Sabab, the reason and al-Shart, condition. Tanqih al-Manat, clearing the cause from any external feature. The analogy in al-Hudud and worships. The legitimacy of using the analogy as a source for reasoning.