Al-Mustadrak ala as-Sahihayn

المستدرك على الصحيحين

A collection of hadith that al-Hakim argued meet the criteria of al-Bukhari and Muslim but were not included in their Sahih collections. Contains approximately 8,800 narrations. While scholars like adh-Dhahabi noted that al-Hakim was sometimes lenient in his grading, the work remains an important supplementary source to the two Sahih collections.