What does modern civilization owe to the ancient Greeks, other than the Olympics and the idea of democracy? If someone asked me, I’d say that their most important legacy is scientific discourse: Greek philosophers invented a way of talking about causation without recourse to theology; they devised the notion

of categories and the abstract nouns that described them. At the same time, there is their nonscientific legacy of Greek mythology: The notion of an odyssey, reunion after hardship, or marriage as reward for a young woman, all come to us from the plot lines of Greek stories, re-told and transformed by Romans and Europeans whose education consisted of reading Latin texts.

But many of our modern obsessions also have recognizable Greek counterparts, as Simon Goldhill shows us in his engaging new book, “Love, Sex, and Tragedy” (University of Chicago Press, 345 pages, $27.50): We are who they were, even though we do not realize it. Mr. Goldhill, a professor of Greek literature and culture at Cambridge University, takes us through the looking glass into antiquity and shows us some of the sights that he thinks most interesting and informative. Philosophy and scientific discourse are not on the itinerary, but there are many new sights, and anyone who goes on the journey will be amused, surprised, and enlightened.

He begins with the ideal of the beautiful body, male or female, and the need to maintain it. Our word diet comes from diaita, the ancient Greek word for regimen. Then there is our preoccupation with sex – also a focus of ancient poetry and art. Ancient men were as concerned as modern men with (shall we say) the evidence of virility, as indicated by the displays on absurdly prurient ancient objets d’art displayed in chic homes in Pompeii, the Roman Malibu.

There are important differences. Pederasts in ancient Greece might be men of substance and property who helped to educate and nurture the youths they favored. Marriage, by contrast, had no such connection with romance. The Oedipus complex was Freud’s invention. If an ancient man dreamt that he slept with his mother, the dream interpreter asked how, not why, because that might predict the likely course of his political career.

Christians responded to the ancient Roman predilection for sex by supposing that people would derive even greater pleasure from abstinence. Stories about the saints were modeled on ancient novels about separated lovers, but with a new emphasis on the gratifications of chastity. St. Thecla falls in love with St. Paul’s discourse, not his physical body, and herself becomes a preacher of God’s word. St. Andrew seduces the matron Maximilla away from her husband to a life of celibacy and piety. The tensions created by this new emphasis on denial have plagued the Church ever since.

While Christian writers were transforming ancient love stories into moral fables, Christian artists turned winged Victories into angels. Educated Christians incorporated Greek philosophical ideas into their narratives. According to the Gospel of John, Jesus is the logos or discourse of God. Plato’s “Republic” lies behind St. Augustine’s “City of God.”

Mr. Goldhill’s rapid and eclectic tour of the Greek legacy pauses for a brief look at democracy, though thankfully without self-satisfaction. In ancient Athens only propertied men could vote; it was really a large oligarchy, the rule of a privileged minority. Democracy in its evolving manifestations is worth preserving because it is less unsatisfactory than any other known system of government: One abiding advantage is that democracy invites self-criticism. Others include freedom of speech, equality before the law, and accountability.

Despite all these advantages, however, democracies are capable of egregious error and willful disregard of their cherished principles. The Athenians condemned Socrates because he asked too many questions. When his pupil Plato designed an ideal state, it resembled Sparta rather than his native Athens. Sparta, not Athens, was the model for the Third Reich.

Mr. Goldhill concludes his tour with some provocative observations about ancient modes of entertainment. In Athens the state sponsored tragedies that portrayed heroes as troubled men and women, raised questions about overconfidence, and reminded the audience of the horrors of war. At the same time, and sometimes literally on the same day, the state sponsored comedies that satirized its cherished institutions and leading politicians. The Romans, especially the Roman Emperors, amused its public with gladiators and men and women battling animals. We are still fascinated by the power of the crowds that could vote against or in favor of life. Shouldn’t we also ask why we like violence in films and television?

Other survivals include the Seder service, which follows the structure of a Greek drinking party or symposium, in which the Athenians liked to remember that they were once oppressed victims of a tyrannical despot. In the political arena, Americans still like to think of themselves as advocates of freedom against a despotic enemy, whatever the reality. We must be mindful of another Athenian legacy, the question raised in Sophocles’ drama Oedipus Tyrannus: “Do you know who you are? Do you know where you come from?” Americans, take note: It is just when you think you know the answer that you are likely to be wrong.

Ms. Lefkowitz is Andrew W. Mellon professor in the humanities at Wellesley College and author, most recently, of “Greek Gods, Human Lives” (Yale University Press).