Commentaries from many cultures and scholarly fields have been edited and studied increasingly over the past years, from a variety of perspectives, above all for their explicit and implicit exegetical methodologies and for the light they can cast upon the texts they comment upon. In this interdisciplinary collaborative project, we would like to try the experiment of examining commentaries from a slightly different perspective, that of the teaching and research ends for which they serve as means, within the educational institutional contexts within which they were produced, transmitted, and used. Our hope is that by focusing upon commentaries in two important scientific scholarly fields, medicine and the mathematical sciences (this latter conceived broadly) but by expanding the traditions examined to include Mesopotamian, ancient Greek, Chinese, those of the Indian subcontinent, and Syriac, we will be able to create useful dialogue among specialists of comparable expertise and understand better which forms of commentary are widespread (and why), and which ones are more locally limited. A preliminary workshop at the Max Planck Institute for the History of Science from Thursday 25 to Saturday 27 August 2016 may be followed by a collaborative volume on the issues involved.