Sefer Hakhmoni by the 10th-century Jewish polymath Shabbatai Donnolo is one of the first texts written in Hebrew in medieval Europe and one of the most important documents of the "e;Hebrew Renaissance"e; of Byzantine Jewry in southern Italy between the 9th and the 11th centuries. Written as a commentary on Sefer Yeiirah (Book of Formation, an anonymous text probably written in Palestine between the 3rd and the 6th centuries), Sefer Hakhmoni is in fact a much more complex work, consisting of biblical exegesis, astrology, medicine, a detailed analysis of the neo-Platonic idea of melothesia, and the correspondence between the elements of the microcosm and macrocosm. This volume offers the critical text, an annotated English translation, and a comprehensive introduction to Donnolo and his works.