In ancient Mesopotamia, days were interpreted as inherently positive or negative, which affected the results of activities or what happened on that day. This doctrine of essentially good and bad days was documented in a group of calendrical texts called "hemerologies" in modern terminology. Hemerologies determine whether a certain day is positive or negative. In addition, we have texts that ask about the appropriateness of a certain activity based on the quality of the day. These texts thus offered advice on everyday life about whether the desired action should be carried out or not on the day in question. - The aim of this work is to present a systematic presentation of hemerologies from Mesopotamia in the first millennium BC with thematic studies on various aspects. The study begins with a general overview of hemerologies in ancient Mesopotamia (Chapter 2): the terminology in modern scholarship, the divinatory tradition to which hemerologies belonged, as well as the sources and their temporal and geographical distribution.

Chapter 3 presents the calendars that served as the basis for the temporal orientation of the prescribed activities of the hemerologies and of everyday life. Chapter 4 deals with the collective tables and compilations that are products of scholarly editorial work. On the one hand, their creation reflects a certain interest of the authors, which is a key to the use of hemerologies in practice. On the other hand, the active processing of the existing texts through compilation is important when considering the role of the hemerological corpus in the scholarly tradition and the question of standardization. Chapter 5 explains the logic and systematics by which a certain hemerological idea was associated with a specific calendar day. Chapter 6 examines how hemerologies were used in practice, based on the texts themselves, the archival context, and the texts that cite or refer to hemerologies (chapters 6.1–4). They provide information on the people who copied and studied hemerologies, as well as on the academic, political dimensions of hemerologies, while subsection 6.5 examines the social influence by comparing it with everyday texts. The last chapter presents the changes in the hemerological tradition in the last centuries of cuneiform culture and the influence of Mesopotamian hemerologies on later ancient cultures.

The study is supplemented by editions of 14 selected hemerologies, hemerological compilations and relevant texts (transcription, transliteration, translation and commentary) that have not yet been published, have only been published in autographs or that update the known text with newly identified text representatives. The appendices provide a systematic overview of evaluated letters and royal inscriptions as well as dated everyday documents (marriage certificates, purchase documents) and requests for viewing sacrifices, which were used to examine the practical use of the hemerologies in Chapter 6.