Hadith, the collected traditions of Prophet Muhammad, are the second source of Islamic law after the Qurʾan. The Sahih of al-Bukhari is the most authoritative collection of hadith in Sunni Islam, and Fath al-Bari by Ibn Hajar is one of the most important commentaries on the Sahih. While al-Bukhari has been available in English translation since 1971, Ibn Hajar is only being translated now. Ælfwine Mischler was asked to write multiple indexes for the translation of this multi-volume classic Islamic text. In this article, she describes the nature of Ibn Hajar’s work, some of the challenges in indexing it, and her solutions for writing both cumulative and single-volume indexes.