Usool al-Fiqh wa Ibn Taymiyyah أصول الفقه وابن تيمية 
ash-Shaykh al-Islaam Ibn Taymiyyah didn't write any books in Usool al-Fiqh but If he did this would be the closest representation of it. This book speaks about the life of ash-Shaykh al-Islaam Ibn Taymiyyah, The Fundamentals of Ibn Taymiyyah, It compares the Usool of Ibn Taymiyyah with that of al-Imaam Ahmad bin Hanbal, Ibn Qayyim and those from Ibn Taymiyyah's family. It also speaks about Ibn Taymiyyah's stances on such issues as Istisahab (Continuity) and Istanbat (Deriving Rulings), Also it speaks about those who deny al-Ijamaa'. Written by Doctor Saalih bin 'Abdil Aziz Ale Mansour (Rahimahullaah).  Printed in one huge volume on 742 pages of yellow paper.