This course studies the following principles of Islamic Jurisprudence. Al-Istihsan i.e. adopting a ruling which is different than the similar rulings in the subject to which the issue in question belongs and considering this choice as being better than the other possibilities. Sad al-Dhara’i‘, preventing the means of evil. Al-‘Urf, custom. Qawl al-Sahabi, the opinion of the companion. Al-Istishab, presumption of continuity. Al-Masalih al-Mursalah, consideration of public interest. Besides, this course clarifies the impact of these principles on tackling the new cases.