In Philip Roth’s “The Human Stain,” Coleman Silk, a professor of classics at Athena College, asks his class about two absent students. “Does anyone know these people? Do they exist or are they spooks?” The students are black and complain to the dean. Silk protests that he was using the word spook “in its customary and primary meaning … as a specter or a ghost,” but it goes for naught. His career is over, his life soon to follow.

But classics professors have problems with race outside fiction’s counter-life, as Mary Lefkowitz’s “History Lesson: A Race Odyssey” (Yale University Press, 202 pages, $25) makes very vivid. In 1993, Ms. Lefkowitz, a professor of classics at Wellesley, attended a lecture by Yosef ben-Jochannan, author of “Africa: Mother of Western Civilization.” In his lecture, Mr. ben-Jochannan repeated the central claim of his book: that Aristotle had stolen his philosophy from the Egyptians, wholesale, a charge to which Ms. Lefkowitz’s husband audibly answered from the audience, “Rubbish.” Heated words were exchanged, and Mr. ben-Jochannan’s defenders — primarily Ms. Lefkowitz’s colleague Anthony Martin, whose courses feted Mr. ben-Jochannan’s work — raised an alarm: A Jewish conspiracy against blacks was afoot, they charged, with Ms. Lefkowitz directing the protocols.

Such charges don’t usually bother themselves with evidence, and this one was no different. But college campuses in the 1990s were peculiar places. A poorly chosen (“spook”) or impolite (“rubbish”) word could turn a cold cultural war hot. Especially when one of the parties was a classicist — defender of a centuries-long academic tradition — and the other an Africanist — defender of a tradition that achieved intellectual respectability only recently and, sadly, against the fusty stubbornness of many classicists.

At the time of the incident, Ms. Lefkowitz was already on the radar of a number of Jewish-conspiracy theorists. She had reviewed — in the “conservative, Jewish-owned New Republic” (to use Mr. Martin’s words) — a two-volume polemic against Greek civilization by Martin Bernal, a sociologist at Cornell. Mr. Bernal’s work, “Black Athena,” had alleged that classical scholars had not only failed to acknowledge the debt Greece owed Egypt, but that they were actively suppressing that debt (a conspiracy within a conspiracy, in other words). Her review was evidence enough that she, again in Mr. Martin’s words, had dug in her heels against “Black progress.”

Ms. Lefkowitz had actually gone easy on “Black Athena.” And her husband’s riposte was quite gentle itself. The charge, remember, was that Aristotle had hopped a boat from Athens, strolled into the library at Alexandria, grabbed a bunch of books, brought them back to Greece, and put his name on them. This is almost so unbelievable that it has to be true — but, alas, it isn’t. First, there is no record of Aristotle ever having gone to Egypt. Maybe that evidence was suppressed? Perhaps — but there wasn’t even a library in Alexandria for Aristotle to pillage during his lifetime. It wasn’t built until at least 297 BCE; Aristotle died in 323 BCE. Even if he had wanted to steal the Egyptians’ “Metaphysics,” “Poetics,” or “Politics,” he wouldn’t have been able to find them in Alexandria.

What, then, should we do about such nonsense — used in its “customary and primary meaning” of “assertion in the utter absence of evidence”? This, in many ways, is the central question raised by “History Lesson.” Ms. Lefkowitz finds that it isn’t going to be answered by academic administrators, whose job, she tells us, is mostly to keep the peace. When Ms. Lefkowitz asked that a course offered by Mr. Martin be changed to reflect more accurately the historical record, she was told, “He has his view of ancient history and you have yours.” This casual intellectual equivalence shows a remarkable dedication to keeping the peace, indeed.

But that attitude, Ms. Lefkowitz’s book shows, certainly did not keep the peace. It only added to the rancor. Nor did it help cultivate the university’s mission: the production and dissemination of knowledge. If everything counts as knowledge, of course, then nothing does. In the academic climate Ms. Lefkowitz recounts, knowledge and politics were no longer distinct pursuits. But they are distinct and, if either is to be pursued successfully, ought to remain so. This, of course, does not mean that knowledge cannot be brought to bear on political problems; only that politics cannot dictate what counts as a worthy contribution to our understanding of ourselves.

The ancient library at Alexandria might be described as the first attempt to collect and systematize those worthy contributions. Ms Lefkowitz has made many such contributions. Her story, unlike Coleman Silk’s, ended happily. Reasonableness and civility won out. Philip Roth would never have let that happen. So much the worse for him. But both have given us work that will long outlast our mortal lives, work that might even find a home in a library in Alexandria. The Egyptians recently finished rebuilding it.

Mr. Boyle teaches classics at the University of North Carolina at Chapel Hill.