(Larry Hurtado): Although it’s been out for several years now, I’ve only recently become introduced to a major and important, multi-volume reference work on virutually all aspects of religion in the ancient Greek and Roman periods: Thesaurus Cultus et Rituum Antiquorum (5 vols., Los Angeles: J. Paul Getty Museum, 2004-2006). For advanced research on the religious environment of earliest Christianity, this work will be valuable, offering up-to-date discussions of matters by a galaxy of experts. Also, the volumes include photos of items illustrative of the topics discussed (e.g., cult objects, temples/shrines, representations of worship/prayer/processions, etc.).
The articles (sizeable and with copious bibliographies) are often collaboratively written and variously in English, German, French and Italian. Here are a couple of examples that I found particularly interesting: “Gebet, Gebaerden und Handlungen des Gebetes” (“Prayer, Gestures and Actions of Prayer”), Vol. III, pp. 105-50 (by Daniel Jakov & Emmanuel Foutiras); and “Heroisierung, Apotheose / Eroizzazione, Apotesi” (“Heroization and Apotheosis”), Vol. III, pp. 125-214, by Kostas Buraselis, Ittai Gradel et al.