Al-Mustasfa min 'Ilm al-Usul of Imam al-Ghazali

Al-Mustasfa min 'Ilm al-Usool of Imam Abu Hamid al-Ghazali is one of the most important book in this science is even a pillar among the pillars on which were written in the subject (Ibn Khaldun mentions it among which are to him 4 books indispensable in Usool).

The Imam al-Ghazali wrote several books in this area, and al-Mustasfa is between Tahdhib al-Usool and al-Mankhul. He gathered the various subjects of study that constitute Usool al-Fiqh: Hukm, Maqasid, Adillah Shar'iah, Kitab, Sunnah, Ijmaa, Qiyas, Ijtihad etc.