Saboraic Introductions and R. Moshe Feinstein
Since the 19th century Talmud scholars have been writing about the Saboraic introductions to Talmudic tractates, a phenomenon already pointed out by Rav Sherira Gaon. See here for a recent discussion from a very good, although ridiculously expensive, book. It seems like there is still room for more to be written as an M.A. thesis was recently penned on the subject. In addition, there is an M.A. thesis comparing R. Moshe Feinstein’s responsa, Igrot Moshe, and his commentary on the Talmud, Dibrot Moshe.