How did the Mishnah become the canonical rabbinic work of such influence? To what degree was it, in fact, accepted as canonical, and to what degree did the supplementary and even contrary teachings of earlier rabbis gain traction in the burgeoning rabbinic communities of the Galilee and Babylonia? Before answering these questions, we focus on methodological problems that make confident answers difficult. We begin with the fact that rabbinic “Torah” was, at least to a significant extent, oral, and ask how this reality impacts the nature of the tradition we preserve. We then study the words of the rabbis of the Mishnah’s successor generations, known as Amoraim, and seek to determine how their attentions shaped the text and status of the Mishnah and other earlier rabbinic teachings. In what ways do Amoraim, in their commentaries on earlier teachings, pay respect to the authority of those teachings, and in what ways do they forge their own, new directions? From the laws and commentaries of the Amoraim emerged a new style of rabbinic study that would give birth to two Talmuds and thus shape Jewish culture for generations to come. In this chapter, we learn something about its beginnings.