Mizan al-I'tidal fi Naqd ar-Rijal

ميزان الاعتدال في نقد الرجال

A comprehensive biographical dictionary of hadith narrators who were criticized or disputed. Adh-Dhahabi reviews the judgments of earlier critics with his characteristic balanced approach, often noting when criticism was excessive or when a narrator was trustworthy despite some criticism. It is the most important reference for disputed narrators.