The theme is as old as Homer: A son sets out in search of his missing father. His quest isn’t only to find the man who brought him into the world: It’s a quest to learn who he truly is. The theme takes on added poignancy when reversed, and a father searches for a missing son. He isn’t on a quest for identity; he hopes to recover some part of himself, of his very flesh and bone. His search is an act of restitution. When the Prodigal Son came home, his father killed the fatted calf and ordered a celebration. That unexpected homecoming restored to him something irreplaceable which had seemed forever lost. To recover a missing son restores an essential order to the world; it mends a break in the chain of generations.

This is the premise of Pierre Corneille’s mischievous comedy “The Theatre of Illusion.” Though Corneille, born in 1606 in Rouen, is, together with Racine and Molière, one of the greatest dramatists of France’s “golden” 17th century, he is little known here, largely for lack of good translations. He wrote the play, which he later dismissed as “an extravagant trifle,” in 1635; it had its premiere a year or so before the great tragicomedy of “The Cid,” which brought him immediate success. Unlike the grand and impossibly noble dramas for which Corneille is usually known, “The Theatre of Illusion” is a playful drama, touched by moments of pure farce. At the same time, it offers a shrewd justification of theater. Corneille borrowed the age-old convention, that drama exposes the illusory nature of life itself, and used it to mount an impassioned defense of the stage, his chosen medium.

In French, the play is entitled “L’Illusion comique.” In translating it as “The Theatre of Illusion” (Harcourt, 144 pages, $12), the poet Richard Wilbur brings out its double thrust. The theater is only a glittering reflection of that playhouse of illusion that is life itself. As scene after scene reveals, all the elements of our lives, even those we consider the deepest and most enduring, appear as seductive reflections in a corridor of mirrors. This seems a bleak premise but, for Corneille, that procession of illusions gives life — and theater — its bittersweet zest.

The plot is silliness itself. Pridamant, a grieving father, regrets his harshness toward Clindor, the son whom he drove from home by his strictness. After searching for ten years, he resorts to the services of Alcandre, a wizard. This Prospero-like figure, who enjoys a panoramic view of past and future, shows Pridamant the hidden events of his wandering son’s life. Clindor’s “loves and trials” appear to the father’s eyes as though he were witnessing them through a secret peephole onto a well-lit stage.

Clindor sinks to selling snake-oil remedies from door to door, displays dancing monkeys at a fair, and becomes a hack lyricist, scribbling popular ditties only to find himself, at the end of his rambles, mysteriously ennobled. His character is laid bare before his father’s astonished eyes. He wins the high-born Isabelle but, as it turns out, only for her wealth; he is really in love with her sexy and sharp-tongued maid. As Pridamant watches in horror, Clindor, caught in an adulterous tangle, lies stabbed to death, and Isabelle follows him to the grave.

The melodrama is lightened throughout by the antics of Matamore, a Gascon soldier. Branded “a swaggering fraud,” Matamore gets all the best lines. He brags of slaughtering kings, but his hand trembles at shadows. Corneille claimed years later that Matamore was little more than an incidental character whom he added purely “for laughter’s sake.” And yet, he not only propels the melodrama but serves a more profound purpose: He’s the only character aware of his own delusions. When exposed as a coward, he admits that “fear is my warhorse, my Bucephalus.” He stands as a dramatic foil to the more obstinate illusions of his virtuous despisers.

Corneille had great fun with this character, who also inspires Mr. Wilbur’s finest touches as a translator. He not only catches Matamore’s bombastic accents to perfection but through clever rhymes conveys his absurd grandiosity. When Matamore quakes before a fight, he has him say:

I’ve never trembled so, upon my honor.
The risk’s too great; if they see me, I’m a goner,
For if they dared attack, I’d rather die
Than soil this arm by fighting such canaille.

The rhyme on “honor” and “goner” is amusing not only because it’s unexpected, but because the shift of register from a high-flown word to slang gives us Matamore’s Falstaffian sleaziness in one apt swoop. And Mr. Wilbur is having as much fun as Corneille when he rhymes “die” with the French word “canaille” (“rabble”); the rhyme is simultaneously pretentious and self-deflating. Mr. Wilbur’s earlier translations of Molière and Racine have long been considered classics, and rightly so; this, his first Corneille, is equally marvelous. Not only do the lines flow with superb economy and grace, but the whole version is infused with a wit which manages to be at once biting and unobtrusive. “All his steps are miracles of art,” one character remarks of the wizard Alcandre, and the same might be said of Mr. Wilbur. “The Theatre of Illusion” goes the Shakespearian device of a play within a play one better; this is a play within a play within a play. For at the conclusion, we realize that in fact Clindor has become an actor and the tragic events his shaken father witnesses are merely scenes on a stage. Corneille uses this denouement to defend theater which has become “the talk of Paris, the provincial’s dream, / The pastime which our princes most esteem.” But for Corneille, the theater does more than place our illusions in full view on a public stage. It reveals those same illusions as the very elements out of which human lives must be spun.

eormsby@nysun.com