As a form of writing that reveals the diarist's personality, conveys biographical and genealogical data, contains details of everyday and family life, and provides insight into the past and the sociopolitical and cultural circumstances in which the diarist lived, diaries have been a rich source of information for scholars of various research interests. Diaries that contain a lot of references associated with reading and books are of particular interest to book historians. Based on the content analysis of the diary of Dragojla Jarnević, a famous female author from the period of the Croatian National Revival, this article demonstrates diaries' research potential as sources for the history of reading.