al-Hakim al-Naysaburi

Abu Abdallah Muhammad ibn Abdallah al-Hakim al-Naysaburi (321-405H) was the leading hadith authority of his era in Khurasan, known as al-Hakim (The Master). His most important work, al-Mustadrak 'ala al-Sahihayn, collects hadiths he considered met the criteria of Bukhari and Muslim but were not included in their collections — a claim that subsequent scholars have assessed with varying degrees of agreement. He also wrote al-Madkhal ila 'Ilm al-Sahih, Ma'rifat 'Ulum al-Hadith, and biographies of Shafi'i scholars of Naysabur. Critics, including al-Dhahabi, noted he was sometimes lenient in authenticating hadiths.