The book Usul al-Shashi is a famous and well-known book of Islamic Jurisprudence. Scholars have been involved in teaching this book for hundreds of years. The author of this book is unknown. Some scholars have written the name of the author as Nizam al-Din Shashi, while according to others, the author is Abu Yaqub Ishaq Ibn Ibrahim Al-Khorasani Al-Shashi. The author was a resident of Shash, a village in Khorasan. But this information about the author cannot be definitely satisfied.
Islamic Sharia gives us guidelines in all areas of life so that we can lead our lives in the right direction. The main sources of these Islamic rules are the Qur’an and the Prophet’s (peace be upon him) hadith. However, the details of all the problems are not clearly mentioned in the Qur’an and Hadith. Also, the details of newly occurring issues are not included. May Allah bless the jurists (fuqaha) who extracted millions of issues from the Qur’an and Hadith and codified them in the form of formal knowledge. This knowledge is called jurisprudence. Also, the jurists, being more kind, wrote down regular knowledge for the extraction of problems. This knowledge is called Usul al-fiqh (Principles of Islamic Jurisprudence).
Usul al-fiqh is the name of knowing the rules and regulations by which we know how to derive Shariah rulings from the four evidences (Qur’an, Hadith, Ijma al-ummah, and Qiyas).
