Performance is an idea that became a field. For ideas to matter to the field of performance studies, however, they must take the form of action—a play, a rite, a dance, a game, a parade, an utterance. The action of performance may be practical or symbolic, but it is “always a doing or a thing done” (Diamond, Performance 1). In this essay, I assess the idea of performance, the field of performance studies, and their common relation to action by reopening the question of mimesis, the venerable doctrine that art imitates life. I also provide a preliminary sketch of a practical poetics of performance, defining it as Orphic (of or pertaining to the mythic figure of Orpheus). The action that the Orphic plot imitates—moving forward while glancing back—recapitulates the risky act of performance itself, for the performer typically feels the urge to look back, despite the prohibitions and costs, because performance always seems to be authorized by something prior, even when it isn't. Not restricted to dead Europeans or any other limited constituency, popular Orphism embraces all the lively arts, but it is most intensely concentrated in poetry meant to be spoken aloud, from Homer to hip-hop, and in lyric drama. “The story of Orpheus underlies every poem,” Susan Stewart writes in Poetry and the Fate of the Senses, and she might have added, “every performance”: bereft of Eurydice from the moment of his fatally forbidden turn, when he dooms her to be his inspiration, “he must attempt to fill her absence with compensatory song” (256). So Eurydice stands in for Orpheus, punished for his transgression, and he for her, making art out of her fate. Across the gulf of time and the river Styx, she prompts him, as he keeps looking back to her.