Rabbi Ari Kahn's The Crowns on the Letters represents a major achievement in the study of the lives of our sages, as well as in the study of rabbinic aggada.This work is an immensely learned and deeply creative interpretation of many fundamental aggadot relating both to the intellectual biographies of the tannaim and amoraim Hillel and Shammai, Rabbi Akiva and Rabbi Shimon bar Yochai, Resh Lakish and Rabbi Yochanan, and many others as well as to major themes in Jewish thought including the nature of the Oral Law, mysticism and its perils, the messianic era, teshuva, and Eretz Yisrael. Rabbi Kahn's work is refreshingly original and he wears his erudition lightly, so that this is not only edifying scholarship but readable as well. Rabbi Menachem Genack