In this book, Hayes addresses the central concern in talmudic studies over the genesis of halakhic (legal) divergence between the Talmuds produced by the Palestinian rabbinic community (c. AD 370) and the Babylonian rabbinic community (c. AD 650). Hayes analyses selected divergences between parallel passages of the two Talmuds. Proceeding on a case-by-case basis, she considers whether external influences (cultural or regional differences), internal factors (textual, hermeneutical, or dialectical), or some intersection of the two best account for the differences.