Introduction

Abu Abd Allah Muhammad ibn Abd Allah al-Hakim al-Naysaburi (321–405 AH / 933–1014 CE) was one of the foremost hadith scholars of the fourth Islamic century. Born in Nishapur in Khurasan, he studied under more than a thousand teachers across the Islamic world, travelling extensively through Iraq, the Hijaz, and Central Asia to acquire hadith transmissions from the leading masters of his generation. He served as chief judge (qadi) of Nishapur and was widely acknowledged as the leading hadith authority of Khurasan in his era. His other major contributions to hadith scholarship include Al-Madkhal ila al-Sahih (an introduction to hadith sciences) and Ma'rifat Ulum al-Hadith (Knowledge of the Hadith Sciences), a foundational text in hadith terminology. He died in Nishapur in 405 AH after a long and extraordinarily productive scholarly life.

Al-Mustadrak 'ala al-Sahihayn (The Supplement to the Two Sahihs) is al-Hakim's collection of hadiths that he judged to meet the transmission criteria of Imam al-Bukhari and Imam Muslim — meaning that their chains of narration pass through narrators included in the rijal of one or both of the Sahihs — yet which were not themselves included in al-Jami' al-Sahih or Sahih Muslim. The work runs to four substantial volumes and contains thousands of hadiths across all the major chapters of fiqh and belief. Al-Hakim's stated purpose was to supplement the two canonical Sahihs with material that, in his assessment, met their standards of authenticity and had been neglected or overlooked by the two Imams.

The critical reception of Al-Mustadrak has been one of the most consequential discussions in the history of hadith scholarship. Al-Hakim's judgments of authenticity are widely regarded as lenient — he himself acknowledged that he composed the work in his old age and did not always scrutinise every chain with the rigour he applied in his earlier works. His younger contemporary, the great hadith critic Shams al-Din al-Dhahabi (d. 748 AH), produced a summary (talkhis) of Al-Mustadrak in which he evaluated al-Hakim's gradings hadith by hadith, frequently disagreeing and pointing out narrators whom al-Hakim overlooked or assessed too favourably. This talkhis is typically printed alongside Al-Mustadrak in modern editions and is an essential companion: no hadith from Al-Mustadrak should be cited as authentic without first consulting al-Dhahabi's evaluation of that specific narration.

The practical value of Al-Mustadrak for scholars and students lies in several areas: it preserves transmissions not found in the Six Books, it records the judgments of a major fourth-century hadith master on a large body of material, and al-Dhahabi's accompanying critique provides a masterclass in applied hadith criticism that rewards careful study. Readers should approach the work with the awareness that a hadith graded sahih by al-Hakim alone carries considerably less weight than one confirmed by al-Dhahabi, and that many narrations in the collection carry significant weaknesses. Consulting later evaluations by Ibn al-Qayyim, Ibn Hajar al-Asqalani, and al-Albani on specific hadiths will further assist the student in distinguishing the sound transmissions within this important but uneven collection.