NEW YORK - Ah, Ireland! Martin McDonagh can't say enough about the eccentricities of the Emerald Isle in "The Cripple of Inishmaan," the playwright's darkly hilarious and surprisingly moving comedy, which opened Sunday at off-Broadway's Atlantic Theater Company.

Though London-born, McDonagh, author of "The Beauty Queen of Leenane" and "The Lieutenant of Inishmore," has deep Irish roots, a DNA that have given him a sharp eye for Irish characters and an even sharper ear for the way they talk.

And talk they do in this carefully calibrated revival, a joint production of the Atlantic and the Druid Theatre of Galway, Ireland. McDonagh's attitude is both joyous and jaundiced in its depiction of the colorful residents of Inishmaan, a hardscrabble island off the west coast of Ireland, circa 1934.

In director Garry Hynes, McDonagh has found the perfect midwife to bring the play back to New York, especially after a much different, more cartoonish production 10 years ago proved disappointing. Hynes, who runs the Druid, has tapped into a joint Irish-American cast, and her actors makes a compelling argument for "Inishmaan" as one of McDonagh's finest plays.

Chief among them is Aaron Monaghan as Billy, the heartbreaking title character. Not since Philip Anglim scored off and on Broadway in "The Elephant Man" nearly 30 years ago has an actor so physically inhabited a role. Contorted and consumptive, Billy is the play's pure-of-heart center. He's a lonely lad, an orphan raised by two fussing aunts. And Monaghan's extraordinary portrait proves to be powerfully endearing.

"The Cripple of Inishmaan" concerns the arrival of a Hollywood film crew on a nearby island to film a movie and its search for locals to join the cast. Billy sees the film as his way out of a sad, drab existence. *

Linda Gross Theater, 336 W. 20th St., New York, N.Y., through Feb. 1, $65, 212-279-4200,