The book before us presents, for the first time, a lost Tannaitic midrash on the Book of Deuteronomy, the very existence of which was previously entirely unknown. Passages from this midrash were discovered in the commentary on Deuteronomy by the Karaite sage Yeshuʿa ben Yehuda, a commentary preserved only in manuscript form. These manuscripts are housed in the Public Library of Saint Petersburg, and their study became possible only after the fall of the Iron Curtain. Further traces of the midrash were identified in two medieval rabbinic midrashim: Sefer Pitron Torah and Midrash Ḥadash al ha-Torah. The drashot cited in these sources are similar in nature to those in another Tannaitic midrash, Sifrei Zuta on the Book of Numbers. This similarity is clearly evident in unique terminology, parallel drashot, and the names of certain sages; it is also reflected in the language of both midrashim, their midrashic approach, their teachings, and their halakhot. Therefore, the new midrash has been named Sifrei Zuta on Deuteronomy.