ʿAbd al-Ghanī al-Maqdisī compiled biographical information on transmitters from major hadith collections in al-Kamāl. Al-Mizzī substantially revised and expanded this material in Tahdhīb al-Kamāl, and Ibn Ḥajar later contributed Tahdhīb al-Tahdhīb.
These works are especially valuable for comparing names, kunyas, variant spellings, and critical assessments.
Their contents and arrangements are not identical. A detail found in one should be attributed to that source rather than assumed to occur in each related compilation.