Commentary

n.	1.	A series of comments or annotations; esp., a book of explanations or expositions on the whole or a part of the Scriptures or of some other work. This letter . . . was published by him with a severe commentary. - Hallam.
	2.	A brief account of transactions or events written hastily, as if for a memorandum; - usually in the plural; as, Caesar's Commentaries on the Gallic War.

Noun

1.

commentary - a written explanation or criticism or illustration that is added to a book or other textual material; "he wrote an extended comment on the proposal" Synonyms: comment

affix, allonge, analysis, annotation, apparatus criticus, appendix, coda, codicil, comment, commentation, critical review, criticism, critique, editorial, enclitic, envoi, epilogue, exegesis, footnote, gloss, infix, interlineation, interpolation, leader, leading article, marginalia, notation, note, note of explanation, notice, obiter dictum, observation, postscript, prefix, proclitic, remark, report, review, rider, running commentary, scholia, scholium, suffix, tail, word of explanation, write-up