This Shabbat we begin reading the third book of the Torah: Vayikra/Leviticus. In historic rabbinic circles, this book is also referred to as "Torat Kohanim" or "Instruction to the Priests."
We generally do not think about Judaism having priests . . . but during the millennia in which Israelite religion centered on the portable Tabernacle/Mishkan in the wilderness years through the times of the First and Second Temples in Jerusalem (the last iteration of which was destroyed by the forces of the Roman Empire in 70 ce) it was the Kohanim, the Priestly Class that played a central role in all public rituals and observances. The Kohanim were the experts in matters of ritual, sacrifice and even certain types of disease and environmental contamination.
The Torah book of Leviticus/Vayikra served as their manual of instruction.
It is interesting to me, and I think significant in terms of the ethos of Judaism, that this Priestly Manual was a matter of public record, and not a document that was available only to the Kohanim themselves. Throughout human history, for as far back as we have been able to reconstruct the precepts of organized religion, there has been a tendency to keep access to certain knowledge limited to a closed circle of religious leaders.
This has never been the case in Judaism. Although there were certain rituals and certain observances that could only be performed by a kohein/priest during the millennia during which the Israelite sacrificial cult was practiced, the rules that those kohanim had to learn were accessible in the text of the Torah which was public knowledge as part of God's revelation to the entire people of Israel.
To this day, there is no secret learning that is shared only with rabbis. Understanding the fine points of Jewish law, history, custom and theology requires time and effort. But the richness of our tradition is available and accessible to anyone who wants to delve into it.
What a unique blessing is the very presence of this book of Vayikra/Leviticus in our Torah!