he writes in Mizān al-Iʿtidāl: “Ibn al-Qaṭṭān says, ‘No judgment can be passed on him; nothing is known about him.’ I (al-Dhahabī) remark: I have not included this category in my present book, for Ibn al-Qaṭṭān speaks against every narrator regarding whom no imām who lived in that man’s own time—or one who studied under such a contemporary—has transmitted a statement attesting to his uprightness.
This class is quite numerous; in the two Ṣaḥīḥs there is a large company of narrators of this type—mastūrūn (little-known yet outwardly upright)—whom no critic has declared weak, nor are they to be deemed unknown.” ⦗1⦘

Al-Dhahabī also criticized the book al-Ḍuʿafāʾ by Abū Jaʿfar Muḥammad ibn ʿAmr al-ʿUqaylī (d. 322 AH) for listing among the weak a number of trustworthy transmitters, foremost among them the ḥāfiẓ of his age, ʿAlī ibn al-Madīnī (d. 234 AH). In Ibn al-Madīnī’s biography in the Mizān he writes: “Al-ʿUqaylī inserted him into al-Ḍuʿafāʾ—how lamentable a deed!” When al-ʿUqaylī quoted ʿAbd Allāh ibn Aḥmad ibn Ḥanbal as saying, “My father narrated to us from him, then withheld his name…then abandoned his narrations,” al-Dhahabī retorted, “On the contrary, his narrations from him appear in the Musnad.” This is a crushing rejoinder from al-Dhahabī, and he further adds: “Here is Abū ʿAbd Allāh al-Bukhārī—enough for you—who filled his Ṣaḥīḥ with ḥadīth transmitted by Ibn al-Madīnī.” ⦗2⦘

When critiquing books, al-Dhahabī does not confine himself to pointing out their defects; he often highlights their virtues and distinctive merits as well. We have already seen him state that al-ʿUqaylī’s work is beneficial ⦗3⦘; he said of Ibn ʿAdī’s al-Kāmil (d. 365 AH) that it is “the most complete and most eminent of the works in that field” ⦗4⦘, and in the biography of al-Dāraqutnī (d. 385 AH) he wrote: “If you wish to behold the brilliance of this unparalleled imām, read his Kitāb al-ʿIlal; you will be astonished and your amazement will only grow.” ⦗5⦘