N. dissertation, treatise, essay, thesis, theme, monograph, tract, tractate, tractation, discourse, memoir, disquisition, lecture, sermon, homily, pandect, excursus, commentary, review, critique, criticism, article, leader, leading article, editorial, running commentary, investigation, study, discussion, exposition, commentator, critic, essayist, pamphleteer

V. expound upon a subject, dissert upon a subject, descant upon a subject, write upon a subject, touch upon a subject, treat a subject, treat a subject thoroughly, treat of a subject, take up a subject, ventilate a subject, discuss a subject, deal with a subject, go into a subject, go into a subject at length, canvass a subject, handle a subject, do justice to a subject, hold forth, discourse, delve into

Adj. discursive, discoursive, disquisitionary, expository