Why bother to read the Classics today? Haven’t those ancient Greek and Latin books gone way past their user date? Can we afford the luxury of spending time on them in this modern world?

Yes we can - or that is what we argue in our book, Twelve Voices from Greece and Rome: Ancient Ideas for Modern Times. One of the reasons for reading these texts is simply that they are so good, and our twelve authors are among the best. Some readers may find Sappho or Horace striking home, as they talk of love or growing old (or, in the case of a Sappho poem recently discovered and published just in time to be included, of a sister's fears for her wayward brothers); some will prefer the hard-edged analysis of Thucydides or Tacitus, or the risk-taking narrative of Caesar; some may simply like the fun of Lucian, imagining how disconcerted the smooth god Hermes would be when the goat-horned Pan greets him as "Dad".

The quality, however important, is only one of the things that this book is about. We also face head-on the question of “ancient ideas for modern times”, and probe deeper into the reasons why these texts could continue to mean so much to people in a very different modern world. Why, for instance, did the Nazis care enough about Tacitus’ Germania to want to steal the manuscript from an Italian mansion? Tacitus requires us to consider precisely what we can learn to our benefit from the past. Can writing the history of despotism, as Tacitus does, help to free the world from its disease?

Why is it that international relations theorists spend so much time on Thucydides, and find him speaking very directly to modern power-politics - but do they overdo it? Problems of imperialism loom large in the history of Herodotus, as he describes the glorious freedom-fighting of the Greeks as they struggle with, and finally overcome, the invading masses of autocratic Persia: but is his history a foundation text of racism and smug western assumptions of superiority over Orientals? Or is it a critique of those assumptions, suggesting that these Greeks, even these democratic Athenians, are not ultimately so very different after all?

There is a lot of striking rhetoric in these texts on, for example, duty, sacrifice, patriotism and citizenship. But if Barack Obama’s rhetoric might make him the new Cicero, why do his enemies see him as a new Caesar instead? Is Caesar’s own account of his own triumphant yet genocidal campaign a safe text to put in the hands of the young?

Still on warfare, what about Homer’s Iliad? “Stand in the trench, Achilles….”, is the cry of the first-world war poet Patrick Shaw-Stewart: how could it be that Homer’s Achilles, the most special of special cases, could mean so much to some amid the horrors of the trenches?

And is the Iliad only a tale for boys, or is it Homer’s women who really understand what war is all about? Are there other areas too where we can find a distinctly woman’s voice? There’s Sappho, obviously; and how much difference does it make that her love was same-sex? Later figures in the ancient world dwelt on her sexiness rather than her sexuality, but are so many moderns so wrong to read her differently? Is love between two females presented as a more equal relationship than heterosexual love?

What, too, do we make of Euripides’ Medea, as she decries the dual standards of society when it comes to failing marriages? “I’d stand in the front line of battle three times rather than give birth once,” she cries. What would a shocked male in the audience make of that, and is there any answer he could possibly give?

And why do we cry for Virgil’s Dido? Is her sacrifice for Rome’s destiny unfortunate collateral damage, just regrettable necessity, or do her unbearable love and her suicide invite us to share in the suffering that imperialism causes? Is Horace really fit only for the middle-aged? When winter is replaced by spring, do we appreciate (as he does) that there is no cycle of seasons to our own lives. Only death follows on our winter.

What does carpe diem, that perennial favourite for tattoos, actually mean? (Not, in fact, just “seize the moment”.) Do we sneer along with the satire of Juvenal or of Lucian, or find them the butts of their own posturing wit? How far would we really go along with rants against immigrants, aristocrats, the nouveaux riches, prostitutes, transvestites or uppity women? And do Lucian’s gods undermine belief in religion, or might we wonder if polytheism might make more sense than monotheism after all?

This book, based on our contributions to a Radio 3 series, deals with our own and others’ “conversations” with twelve classical authors. That notion of a conversation is important to us: we have chosen texts to which readers can keep going back, and bring new questions, find new things, and go away with new reactions.

We have certainly chosen writers that have meant a lot to us personally as readers, as teachers, and in several cases as the teenagers we once were. The convent girl reading Tacitus furtively in the lunch-break for the juicy bits and the Welsh grammar-school boy on a caravan holiday who can’t wait to get back to the Odyssey - both make their appearance.

What matters more, though, is these authors’ capacity to stimulate thoughts and reflections about the modern world: “ancient ideas for modern times”, indeed.

“Why should I mention Io?”, sing the chorus in A.E. Housman’s Fragment of a Greek Tragedy, playing on the mythical heroine Io, one of many girls that Zeus fell for. It is the sort of thing that tragic choruses often say. “Why indeed?”, Housman wickedly makes them go on; “I have no notion why.”

We have tried to give some of the reasons why Io and all those other figures and texts might indeed still be worth mentioning, reading about, and thinking about. We hope that our readers will be prompted to some good conversations of their own.

Twelve Voices from Greece and Rome: Ancient Ideas for Modern Times, published by Oxford University Press at £18.99