The Book of the Covenant (Sefer ha-Brit) was one of the most popular Hebrew books read by modern Jews, as reflected in 40 editions spanning two centuries, including three Yiddish and six Latino translations. Part scientific encyclopedia, part manual of mystical ascent, and part plea to Jews to embrace a universal ethics, the work was widely influential in an era of radical change and internal debate for Jews as well as for others. The amazing popularity of the author, the Eastern European Jew Pinchas Hurwitz (1765-1821), stemmed from his kabbalistic pedigree. He offered his readers an exciting compendium of scientific knowledge they could read in their holy language under the pretext that its acquisition fulfilled their highest spiritual goals.