الأوسط من السنن والإجماع والاختلاف-ابن حزم

This is the masterpiece of the Mujtahid Imam, Abu Bakr Ibn al-Mundhir d.318ah.

An expert muhaddith and faqih, this work is famous for the following:
1- It is one of the largest collections of athar of Sahabah with asanid, after the musannafs of Ibn Abu Shaybah and Abd ar-Razzaq.
2- It is probably the most detailed early work on the opinions on each mujtahid with the adillah of each.
3- It contains many ahadith and athar with sanad, not found elsewhere
4- It is considered a very reliable work on naql of ijma and ikhtilaf amongst the a’immah.

This is the best print of the book, edited using whatever manuscript portions of the book are existent today. A portion of the book, covering zakat, fasting and hajj is non-existent; thus, no complete edition of the book exists.

Listen to this short 2 minute review to understand the status of this great work:
https://www.youtube.com/watch?v=d3cnavt36K8

High-quality edition in 15 volumes.