The clear in the principles of jurisprudence, authored by: Abu Al-Wafa, Ali bin Aqil bin Muhammad bin Aqil Al-Baghdadi Al-Dhufri, (died 513 AH)

Release date: 1440 Number of volumes: 5/1 Type of paper: Shamua It is considered one of the main books of usul in general, and the books of Hanbali usul in particular, as the author benefited from what is in the book of his sheikh Abu Ya'la Al-Farra, and added to it much of his abundant knowledge and extensive understanding.