Instone-Brewer does a quite thorough job of sorting out which sugyot of the Rabbinic literature can be safely dated as pre-70 and examining them for exegetical principles which were applied by the Sages to whom the respective sugyot are attributed. His analysis is clearly in the text-critical vein, in concert with Emanuel Tov and Jacob Neusner, and may in some places lean too far in the direction of more liberal exegesis, but an important and valuable work nonetheless.