Al-Awsaat by Al-Imaam Muhammad bin 'Ibraheim bin al-Mundhir An-Naysabooree This book is printed in 15 Volumes and deals with Issues based on Haadith that have 'Ijmaa or Iktilaaf in them. This Book is proof that Ibn Al-Mundhir reached the highest level of 'Ijtihaad and therefore wasn't bound to any particular Madhhab, although it is unanimously agreed that Ibn Al-Mundhir (Rahimahullaah) was Shafi'i. Al-Dhahabi said regarding him, “The Haafidh, the ʿAllaamah, the faqeeh, A unique scholar, the Shaykh of Al-Ḥaram, and the one who authored books the likes of which have never been written.” Al-Awsaat is Printed by Darul Falah.

al-Awsaat 1/15 الأوسط من السنن والإجماع والإختلاف