This book deals with the sources of Islamic jurisprudence and their importance in deducing the religious rulings. It covers the concept of ijtihād (independent reasoning), its conditions and application and illustrates why it is a practice for experts rather than laymen. It also explains the differences in the levels of expertise of the mujtahids. In fact, there are seven distinct classifications of mujtahid. The book also covers the communication of God as Lawgiver with regard to the conduct of liable persons. It details the difference in probative value of communication based on the extent to which it binds an individual be it absolutely binding, a recommendation or mere permissibility. The reader will be able to understand the difference between fiqh (law) and Usūl al-Fiqh (methodology of law). Fiqh is the law itself whereas Usūl al-Fiqh is the methodology utilized to extract the law.

The relationship between the two disciplines resembles that of the rules of grammar to a language, or of logic to philosophy. Usūl al-Fiqh in this sense provides the standard criteria for the correct deduction of the rulings of fiqh from the sources of Shari'ah (the Qur'an and Sunnah).