 Poetry is an egg with a horse inside. This third grader's explanation so delighted poet, Matia Harvey, that she made this photo illustration of it. There it was, Harvey explains, the perfect definition for why I write poetry. Fragile delight, the crack of bewilderment, the tiny nae of surprise. What is poetry? What can and should it do? How and why do poets write? These questions have been stirring up debate since before 19 BC, when the Roman poet Horace responded by publishing his 476 line poem that's come to be known as Ars Poetica. Translated from Latin, Ars Poetica means the art of poetry. Horace's poem speaks at times in broad declarations like, mediocrity in poets, no man, God, or bookseller will accept. And at times reads more like a how-to guide, offering practical advice like, be concise. Listen up, all you poets out there. Horace also advises that before deciding your work is ready to share, you put your manuscript away till the ninth year. Because you can always destroy what you haven't published, but once out, there's no recall. Ever since Horace's Ars Poetica, poets have been inspired to join the conversation and chime in with their thoughts on the art of poetry. Though Ars Poetica can refer to Horace's poem in particular, it's also become a more general term referring to a poem about poetry itself. In an Ars Poetica, the poet draws back the curtain for a moment, giving the reader a glimpse of their craft and articulating their own answers to the timeless questions, what is poetry? What can and should it do? And how and why do poets write? Let me give you a few examples. Archibald McLeish's Ars Poetica famously ends, a poem should not mean but be. Cheslaw Mewosh's claims, in the very essence of poetry, there is something indecent. A thing is brought forth which we didn't know we had in us. More recently, Elizabeth Alexander, who was chosen by Barack Obama to read an original poem at his first presidential inauguration, uses the refrain Poetry Is in her Ars Poetica number 100, I believe, to offer a cumulative definition. Poetry, she says, is what you find in the dirt in the corner over here on the bus, reminding us that it's not sparked only by profound moments. The overlooked, the overheard, the quotidian details of our lives, Alexander suggests, are just waiting to surprise and delight us in poetry if we haven't already dismissed them as uninspiring. Though those examples talk about poetry in general, an Ars Poetica can also make a more personal, even political, statement. This contemporary Ars Poetica by Jose Olivares addresses his craft alongside the trials his family has faced as Mexican immigrants, illustrating that what he writes about and why are inextricable from who he is and where his family comes from. My work, to write poems that make my people feel safe, seen, or otherwise loved, he says. My work, to make my enemies feel afraid, angry, or otherwise ignored. And later, my work, survival. His refrain, a reminder of poetry's power to wound and to witness, to heal, and to sometimes even save us. OK, let's say you're trying to spot an Ars Poetica out in the wild. Many poets, like those I just mentioned, make it easy for you by titling their poems, Ars Poetica, with a clear nod to Horace. But plenty of poets don't. So it's up to you, as an engaged, perceptive reader, to recognize when a poem like Galway Cannell's The Bear might be portraying not just an animal, but the craft of writing as well. The voice of Cannell's poem is a hunter, and the poem is pretty much all bear all the time. Bear tracks, bear fur, bear blood, bear scat, to the very last line. The poem ends, the rest of my days I spend wandering, wondering what anyway was that sticky infusion, that rank flavor of blood, that poetry by which I lived. Here you might think, wait, since when were we talking about poetry? Well, all along, apparently. With that surprising last line, Cannell encourages us to read the poem again with this new frame in mind. On the first read, we see the speaker grappling with their own animal and instinctual nature. In subsequent reads, we understand that Cannell's poem is also functioning as an Ars Poetica, arguing that a poet needs to be as engaged with their subject as a hunter tracking an animal. The poet needs to be that observant, that determined, Cannell suggests, to come away from the page successful. In Cannell's poem, the bear's meat keeps the speaker alive. Read as an Ars Poetica, it asserts that poetry can be that vital, that essential. As the poet Mary Oliver says in a poetry handbook, poems are not words after all, but fires for the cold, ropes let down to the lost, something as necessary as bread in the pockets of the hungry. So now that you're familiar with Ars Poetica poems, keep an eye out for them. For centuries, they've been making an argument for the power of language and the value of the arts, each one offering its own take on the art of poetry, each one speaking in a new voice to the questions of what and how and why that have been around as long as poets have.