Al-Kifaayah fi Ma'rifah Usul 'Ilm ar-Riwaayah - al-Khatib al-Baghdadi

While Mustalah's books and Usul's books in the Hadith were originally separated, the great Imam Muhaddith, al-Hafidh al-Khatib al-Baghdadi, wrote a unique book bringing together the two sciences.

Al-Khatib al-Baghdaadi wrote dozens of books on the sciences of the hadith, be it musnad, books of mustalah, Adab of Muhaddith or Talib, or on narrators.

Al-Kifaayah is one of his unavoidable and very important works in the science and foundations of the Hadith.