Ibn Sa'd : Kitāb al-Ṭabaqāt al-kabīr. -- ابن سعد : كتاب الطبقات الكبير
A biographical dictionary of important political and religious figures in early Islam by Ibn Sa'd (d. 845/230), arranged according to generation, documenting the first centuries of Islam. See the entry for Ibn Sa'd in Brill's Encyclopedia of Islam for a good overview of this work.
The first modern edition of Kitāb al-Ṭabaqāt al-kabīr was issued in eight volumes (with an additional volume for indices), in Leiden by E. Sachau and published by Brill between 1904-1917. This work is in the public domain and remains an authoritative edition of the Arabic text.
Volume 1, Part 1 -- Muhammad's Life up to the Hijra
Volume 1, Part 2 -- Muhammad's Life in Medina
Volume 2, Part 1 -- Muhammad's Campaigns
Volume 2, Part 2 -- Muhammad's Last Days and Death
Volume 3, Parts 1 and 2 -- Muhammad's Companions in the Battle of Badr
Volume 4, Parts 1 and 2 -- Pt 1: The Muhajirun and Ansar; Pt 2: Willing Converts to Islam
Volume 5 -- Muhammad's Successors and Companions in Medina and Arabia
Volume 6 -- The Kufans
Volume 7, Parts 1 and 2 -- The Basrans and Hadith Folk in Other Lands
Volume 8 -- Biographies of Women
Volume 9, Part 1 -- Index of Persons
Volume 9, Part 2 -- Indices of Places, Tribes, Hadith, Poetry, and Qur'anic Verses
Published as Kitāb al-Ṭabaqāt al-kabīr [Biographien Muhammeds, seiner Gefährten und der Späteren Träger des Islams]. Ed. Eduard Sachau et al. 16 parts in 9 vols. Leiden: Brill, 1904-1917.
Ibn Khallikān : Wafayāt al-a‘yān -- ابن خلكان : وفيات الاعيان
A biographical dictionary giving information on the lives of important figures in Islamic history, arranged alphabetically by name. The author, Ibn Khallikān (d. 1282/681 AH), was was an assistant to the chief judge of Egypt from 1249 until 1261, when he became qāḍī al-quḍāt (chief judge) of Damascus that same year. See the entry for Ibn Khallikan in Brill's Encyclopedia of Islam. Arabic and English versions of this work are available online through the Hathi Trust as follows: