This essay is an attempt to analyze, classify and illustrate different scholarly approaches to the Sanskrit philosophical commentaries as reflected in some influential and especially thoughtful studies of Indian philosophy; at the same time it highlights some specific features involving commentary and annotation in general, drawing from results of studies on commentaries conducted in other disciplines and fields, such as Classical and Medieval Studies, Theology, and Early English Literature. In the field of South Asian Studies, philosophical commentaries may be assessed from various overlapping and not always exclusive points of view, such as preservation of otherwise lost historical information, historical authenticity and reliability, interpretational innovation, spiritual or experiential insight, philosophical creativity, intellectual liveliness, doxographic intent, degree of incidentality, expository breadth and explanatory depth. The essay provides numerous examples taken from classical to early modern philosophical literature, especially of the Brahminical and Buddhist traditions, and also discusses their diverging perception by modern scholars and interpretators.