"Institutio Oratoria" is effectively a comprehensive textbook of the technical aspects of rhetoric. From the eleventh chapter of Book II to the end of Book XI, Quintilian covers such topics as natural order, the relation of nature and art, invention, proof, emotion, and language. Perhaps most influential among the ideas discussed is his examination of tropes and figures, found in Books 8 and 9. “ trope involves the substitution of one word for another, a figure does not necessarily entail any change either to the order or the meaning of words” (Leitch, 156). An example of a trope would be metaphor, the altering of a word's meaning. A figure, on the other hand, gives the words a new aspect or greater emotional value. Figures are divided into figures of thought, which may make proof seem more forceful, intensify emotions, or add elegance or ornamentation; and figures of diction, which is further subdivided into “the grammatical, in which the form of the word creates the figure, and the rhetorical, in which the position of the word is the primary factor” (Gwynn, 88).