There are some formidable obstacles that inhibit a clear reading of On the Sublime. Much of the text is uncertain; it is not clear what the title means or even who the author was. Given that the book is—among other things—a treatise on aesthetics and a guide to writing style, it is not particularly well written. On the Sublime covers several topics, including morality, rhetoric, and form. Without critical unanimity on what the "sublime" in the title means, however, it is difficult to be certain of the organizing principle that structures the work.

Horace's Ars Poetica provides a contrast in every respect. The poet is one of the best-known Augustan writers, and he makes his subject perfectly clear from the outset. The work is well organized, sorting poetry into different types, discussing the strengths and pitfalls of each, and retaining overarching thematic principles such as decorum, delight, and instructive value.