This foundational tool for the study of the Syriac New Testament, mainly the work of Carolus Schaaf (b. 1646), who was lecturer in Oriental Languages 1680-1720, then professor from 1720 until his death in 1729, at Leiden, first appeared in 1717. The first part of the book is a combined lexicon and concordance. Individual word forms are listed in great detail and separately: for example, peal, then pael, etc.; masculine, then feminine, etc.; participle, then infinitive, etc.; verb forms with and without pronominal suffixes are also given separately. Customary lexical comparisons from Hebrew, Jewish Aramaic, and Arabic are also given. The preface to the lexicon surveys the similar efforts of previous scholars. A unique feature of Schaaf’s work is an index of Syriac forms with weak letters, and thus of possible difficulty to find. Two more indices conclude this first part of the work: an index of the Latin definitions, and an index of names of individuals and places (in Latin). The second part is the text of the Syriac New Testament itself, in vocalized Serto, together with a parallel Latin translation, which Johannes Leusden also collaborated on. A lengthy list of variant readings finishes the book.