The learned and prolific Barhebraeus wrote three Syriac grammars: a larger, a smaller, and a metrical one. These two volumes contain a German translation of the large grammar, The Book of Rays. In it, Barhebraeus covers both the eastern and western dialects of Syriac and presents a mine of information on Syriac as it was known by a significant 13th century scholar. Moberg’s introduction surveys the previous scholarship on Barhebraeus’s grammar as well as Syriac grammarians writing before Barhebraeus. Moberg also includes a lengthy textual apparatus at the end of the translation. One especially helpful feature of this work is a long appendix dealing with Syriac grammatical terminology—not only that of Barhebraeus, but also that in use by other Syriac writers—and its connections to Greek and Arabic grammatical terminology; this appendix ends with a German-Syriac index, a Greek index, and an Arabic index. Any reader interested in the history of grammar, and of course Syriac in particular, will want to study Moberg’s presentation of this important work.