I'm deeply interested in Roman religion. I know there are several sources and I have seen several books in the bookstore, but sadly most of what I can find are "mythology dictionaries", which only speak of the gods and goddesses in a row and don't relate them or group them.
So I'm searching for any book or source that speak about Roman religion itself: not only descriptions of gods and heroes, but also what had to be done in the religion, like rituals and ceremonies, festivals, the calendar, the meaning, religious explanations of natural phenomena etc.
Does anybody know more on this topic? Thank you very much in advance.