Sepher Ha’Aruch [Talmudic Lexicon]

Among bibliographers, Moses Marx states this is the second, Tishbi the fourth and Offenberg the fifth, Hebrew book printed. Nathan ben Yechiel (1035-c.1110) served, together with his brothers Daniel and Abraham, as head of the Rome Yeshivah. See for example Aruch, s.v. matok, where Nathan cites an interpretation of his brother Daniel. In that same entry, Nathan cites a comment of “Mazliach.” Mazliach ben Elijah ibn al-Bazak, a disciple of Hai Gaon, taught Nathan in his youth in Sicily. Nathan's work Aruch is of inestimable value, not only as a lexicographic work but as a halachic authority. (See Aruch cited in Tosaphoth, Kethuboth 6a regarding Sabbath laws). Nathan drew on ealier Gaonic traditions, especially the commentaries of Hai Gaon to the Order of Purities. From a scholarly point of view, this editio princeps of the Aruch is superior to the later editions that were printed from a different manuscript. Between the years 1878-1892, Alexander Kohut published a scholarly edition based on seven manuscripts which he entitled Aruch Completum