Gerrit Bos has long been well known for his critical editions of the medical works of Moses Maimonides in their original Arabic versions. The high standard of these editions is widely acknowledged in the academic community.

In this framework, Bos now delivers a critical edition of the Commentary on Hippocrates’ Aphorisms. Bos has, for the first time, used all of the available manuscripts; this is noteworthy because the two manuscripts from Tehran could not be studied until now. The edition of the Arabic original, prepared before this one by this reviewer, had to deal with the fact that the text was not complete and had to be completed by using parts of the Hebrew translations. Presenting a complete Arabic version is in itself a valuable task and justifies the publication of a new critical edition.

The Arabic text is accompanied by an English translation, which is also heavily annotated to facilitate understanding of the commentary. These annotations offer many cross-references and allusions to other medical writings by Galen and other physicians, which help to classify the insights of the commentary to other medical works.

In addition to the Arabic text, the first volume offers critical editions of the three known Hebrew translations, by Moses Ibn Tibbon, Zeraḥyah Ḥen, and an anonymous translator. With these editions, Bos closes another gap in the research into the text. Until now, there was only one Hebrew translation available in print which was, however, not a critical edition of this version.

The second volume contains the appendixes and indexes. It is important to mention that the appendixes, glossaries, and indexes are so elaborate that this part of the book constitutes a second volume, and at the same time a valuable lexicographical reference book that enables a better knowledge of the scientific terms in their medieval Arabic and Hebrew versions.

The first appendix enables a deeper understanding of the tradition of the Hebrew translations: the text of Moses Ibn Tibbon is available in two versions, the original, and one which is contaminated by the translation of Zeraḥyah Ḥen and is extant in one manuscript only (MS Munich, Bayerische Staatsbibliothek, 275). The contamination in this appendix is clearly shown and documented.

The second appendix documents the remarkable fact of the missing aphorisms in the Arabic version of Maimonides’ commentary (7.63–87). Three aphorisms have been preserved in the translation of Zeraḥyah Ḥen and in the translation of Ibn Tibbon that is contaminated by Zeraḥyah's version.

The most valuable part of the second volume is the glossary: here, Bos lists 2,094 Arabic terms that are used in the Maimonidean commentary, together with their Hebrew counterparts according to the three translations. The contaminated version of Ibn Tibbon's translation is not represented in this glossary. However, this is unnecessary, taking into account that the first appendix is already sufficient for this phenomenon. The glossary includes not just medical terms, but also provides a variety of terms whose appearance form a small dictionary of the Maimonidean language and its various Hebrew translations. Thus, this glossary is not only important for readers of Maimonidean texts, but also for those who are interested in the terminology of the medieval medical literature in general. The volume also contains indexes of the three Hebrew translations, of Greek terms, and of technical terms and materia medica.

The two volumes together make an important contribution to our knowledge of Maimonides’ medical attitude, and the second volume in particular serves as a valuable reference book for medical and scientific terminology in general. Considering the value of the second volume, one might hope that in future, all of Maimonides’ medical works could be supplemented with such a glossary; that there will be – possibly online – a complete glossary comprising all Maimonidean terms in their Arabic originals and available Hebrew and even Latin translations to facilitate the understanding of this important figure in the Islamicate scientific community.