Mișbâḥ al-ẓulma wa-îḍâḥ al-khidma ("the lamp of shadows and the illumination of service"), an ecclesiastical encyclopedia in 24 chapters and divided in two large parts. The first part, chapters 1 to 6, is dedicated to dogmatic and canonical matters (theology, hagiography, canon law, biblical exegesis) and the second part (chapters 8 to 24) deals with the office of the various categories of priests from a liturgical and practical viewpoint. Interposed between the two parts is chapter 7, a very valuable catalogue of books by Christian authors of different denominations that were available in Arabic (partly via translation from Greek, Syriac or Coptic) at the time.