I've started to write what I envision to be the last of my essays on Ayn Rand -- this essay is tentatively entitled Our Man in Greece: On the Use and Abuse of Aristotle in the Works of Ayn Rand.
Perhaps the most egregious example of Rand's abuse of Aristotle was her attempt to invoke his authority in her essays on the philosophy of art, which I first noticed many years ago on my first serious reading of Aristotle's Poetics. Several times in her writings she claimed to be maintaining or renewing the Aristotelian tradition of literary criticism. She did this by misquoting Aristotle to make him seem like "romantic realist" or literary moralist, as in the following passage ("Basic Principles of Literature" in The Romantic Manifesto, p. 80):
The most important principle of the esthetics of literature was formulated by Aristotle, who said that fiction is of greater philosophical importance than history, because "history represents things as they are, while fiction represents them as they might be and ought to be."
But the "quotation" from Aristotle here is spurious. It's true that in Chapter 9 of the Poetics Aristotle draws a distinction between poetry (not "fiction") and history, but he does not say what Rand claims he says. Here is my translation of the relevant passage (1450a36-1451b11):
[T]he function of the poet is to describe, not what has happened, but the kind of thing that might happen, i.e., what is possible according to probability or necessity. For the difference between the poet and the historian is not that the one speaks in meter and the other speaks in prose ... but that the one describes what has happened and the other describes the kind of thing that might be. Thus poetry is more philosophical and more serious than history, for poetry speaks more of the universal, whereas history speaks more of the particular; and by universal I mean what such or such a person might say or do according to probability or necessity (which is the aim of poetry, although it assigns proper names to the characters), whereas by particular I mean what, say, Alcibiades did or experienced.
The primary difference here is that Rand imputes a moral force to Aristotle's interpretation of poetry: it represents things as they "ought to be", she claims. Yet the word "ought" is nowhere to be found in Aristotle's text; his contrast is between the particulars of what has happened vs. the universals of what might happen, not naturalist mere facts vs. romanticist high ideals. Although Rand thought that she was buttressing her argument for the primarily moral purpose of literature by invoking the authority of Aristotle, in fact she was merely abusing that authority by putting words into his mouth.