Ousoûl al fiqh, commonly translated into French by the foundations of law or the Theory of law, consists in traveling to meet God (tptm) and to better know and understand His Speech.

Ousoul al fiqh are the sources of Muslim Law. They are divided into two categories: on the one hand, the fundamental sources (al asliyya) which are the Koran and the Sunna: the Revelation (al Wahy), and on the other hand the derived (taba'iyya) or dependent sources: al ijmâ', (the Consensus), al qiyas (the Analogy).

Usul al fiqh is one of the feats of Muslim legal thought.

Through its definitions, its history, the presentation of its currents and its mechanism. Dr. Hassan Amdouni offers law specialists and students a complete and methodical work on this science. the principles of law schools in the development of their secondary rules (al fouroû') from the ousoûs of their school.

While referring to Arabic sources, the author has adopted, as usual, an approach that combines theory with practice so that this science is not perceived as an abstract and out of reach science.