Al-Hakim and His Supplement to the Two Sahihs

Muhammad ibn Abdallah al-Hakim an-Naysaburi (321–405 AH / 933–1014 CE) was one of the preeminent hadith scholars of the fourth and fifth Islamic centuries, based in Nishapur (Naysabur) in Khurasan (modern northeastern Iran). He served as the chief judge (qadi) of Nishapur and was known by the title al-Hakim (The Wise), reflecting both his judicial role and his towering scholarly stature. He was a prolific author in the hadith sciences, composing numerous works on hadith terminology, narrator biography, and the knowledge of the Quran, though al-Mustadrak is by far the most significant and most used of his works.

Al-Mustadrak ala as-Sahihayn (The Supplement upon the Two Sahihs) is al-Hakim's collection of hadiths that he believed met the authenticity standards of Imam al-Bukhari and Imam Muslim but were not included in either of their Sahih collections. The title literally means the supplement or recovery — hadiths recovered and presented as meeting the criteria of the two canonical Sahih works.

The project rested on a specific claim: that al-Bukhari and Muslim, despite their extraordinary care and comprehensiveness, inevitably left out some hadiths that met their standards, either because those hadiths had not reached them or because of other circumstances. Al-Hakim proposed to supplement their collections with these overlooked narrations.

The work was enormously ambitious and contains approximately 8,800 hadiths organized thematically, covering the full range of Islamic legal and doctrinal topics. Al-Hakim graded hadiths throughout the collection, claiming that each one met either al-Bukhari's criteria, Muslim's criteria, or both. He also included important traditions on the merits of specific Companions, surah commentaries drawn from the hadith literature, and sections on history and biography.

Al-Hakim invited adh-Dhahabi to summarize and critique the Mustadrak — though adh-Dhahabi's summary was actually produced independently rather than at al-Hakim's invitation — and adh-Dhahabi's Talkhis al-Mustadrak has been printed alongside the Mustadrak in virtually all subsequent editions.