Al-Sunan al-Wusta

Al-Sunan al-Wusta, (السنن الوسطى), or Marifat al-Sunan wa-al-Athar (معرفة السنن والآثار) is a hadith work compiled by Imam al-Bayhaqi (384 AH – 458 AH). It is multi-volume book which provides a compilation of textual evidences for Shafi'i jurisprudence.

Description
This book is considered to be one of the most important Shafi’i books, as it collected the hadith evidence of the school of thought, a way out for it from the Sahih and Sunnah, showing its methods, the reason for what was faltered from it, and the reason for Al-Shafi’i inferring it if it was faltered. Al-Bayhaqi also explained the doctrines of the followers and those after them, such as Abu Thawr, Al-Hasan al-Basri and Ahmad Ibn Hanbal, and he arranged it according to the arrangement of Al-Muzani. The old sayings of Al-Shafi’i are sometimes cited, and the book has some comments from the transcription of a hadith, the translation of a scholar, and attribution to a reference.

Reception
Ibn al-Subki said: "No Shafi'i jurist can do without it," while his father, Taqi al-Din al-Subki said: "He meant by the title: Al-Shafi'i's Knowledge of the Sunnahs and Reports (Athar)."

A dream of al-Shafi'i carrying sections of this book in his hand occurred to one of the right-acting men when al-Bayhaqi was writing Ma'rifat as-Sunan wal-Athar. He was stating, "I have read them," or, alternatively, "I have written seven sections of the Book of the jurist Ahmad (al-Bayhaqi)."