On Legal Theory of Muslim Jurisprudence

Al-mustasfa min 'ilm al-usul () or On Legal theory of Muslim Jurisprudence is a 12th-century treatise written by Abū Ḥāmid Muḥammad ibn Muḥammad al-Ghazali(Q.S). While Ghazali was deeply involved in Tasawwuf and Kalam, Islamic Law and Jurisprudence formed the core of his concerns.
Structure.
Most of Ghazali's activity was in the field of jurisprudence and theology. He completed this book towards the end of his life. The book described:
The Sharia rules.
The sharia rules were further categorized into following.
The Sources of the rules.
The sources of the rules included.