This course aims to study the subjects of Reasoning, Imitation, and al-Istifta’ i.e. asking for a legal opinion. These issues belong to the Science of the Principles of Islamic Jurisprudence. In addition to this, it points towards assessing the importance of reasoning in the contemporary time and the role of the Islamic legal councils in performing it. Thus, the following subjects are taught in this course in order to achieve these targets. The definition of reasoning, the personal reasoning, the analogy, the relationship between the reasoning and the Science of the Principles of Islamic Jurisprudence. Al-Mujtahid, the jurist, his status, his conditions and the levels of al-Mujtahidun. The scope of reasoning and its rulings. Reasoning in the contemporary time, its importance, our need to it, the joint reasoning which is carried out by a group of jurists, the Islamic legal conferences and councils.