The Prophet (PBUH) said: “If Allah intends good for anybody then he gives him understanding (fiqh) in deen”. It is not possible for the one with understanding (fiqh) to be without usul al-fiqh or for the usuli (the one who knows usul al-fiqh) to do without fiqh if he wants to have understanding (of the deen). – Shaykh Al-Uthaymin, Kitab Al-Ilm This book is the first of the Usul Series, which consists of various books of the Principles (Usul) of the religion.