Temple-like small buildings played an important role in the ensemble of buildings constructed in Hellenistic times in the theatre area at Aigeira, due to their remarkable multiple presence. The three best preserved - Naiskoi D, E and F - are the main focus of this project. The book presents new detailed plans, a photogrammetric 3D-model, the analysis of the architectural and archaeological evidence, reconstruction drawings as well as the interpretations of the three small buildings that have been excavated mainly in the 1970s and 1980s by the Austrian Archaeological Institute. The architectural and typological study of the three buildings has led to new results concerning their building history, architectural design and function. The prostyloi that were built in the course of the third and second centuries BCE show differences in proportions, building techniques and interior features. The evidence regarding the interior layout indicates that additionally to the initial main function as temples, the use as dining halls was added, and could even have played the main role in later times. New conclusions for the entire theatre area can be drawn: Rather than planned and built in a single building programme, the ensemble that is now interpreted as a sanctuary was gradually developed during the Hellenistic period, probably accompanied by a shift of meaning. Using the case study of Aigeira, the role of the relatively frequent naiskos building type in Hellenistic sanctuaries could be explored in-depth in its context.