SAM Shepard's new play Kicking A Dead Horse was written especially for Stephen Rea, which must be one of the highest compliments an actor can be paid, especially by a playwright who is considered one of the best of his generation. The world premiere took place on Thursday night in the Peacock theatre and seemed a strangely muted affair, despite the momentousness of the event.

The play tells the story of Hobart Struther, a wealthy New York art dealer, who has ditched his shiny city life in search of authenticity in the modern-day wild west. It begins with the absurdist sense of comedy that Shepard has become known for.

The set is covered with a sky-blue silk sheet, obscuring oddlyshaped mounds. As the music rises, the sheet is pulled slowly from the side of the stage to reveal mounds of earth, a deep pit and a dead horse (which looks very real). The audience titters.

From the pit in the centre of the stage, a spadeful of dusty muck gets thrown out, followed by a subterranean grunt, then another spadeful, another grunt, another spadeful, until the spade gets thrown up and a dusty Rea slowly emerges.

The first few minutes of the play are all physical comedy; he gives the horse a good kick (he does this several times throughout the play) before starting into his monologue, which is so well-performed and well-written it keeps the audience riveted right through to the end.

Shepard is de-romanticising the mythology of the American cowboy. As night falls and Struther is stranded in the desert with his bags, a faulty tent and the rain and lightning flashing about him, it becomes apparent that finding authenticity through some quixotic ideal is not as easy as it might look. Struther tells himself, "So this is the way you wind up - not like some gallant bushwacker but flattened out babbling in the open plains."

Shepard mocks him even further by reminding him of the wife or partner that Struther has clearly left behind to go on his one-man mission to find himself.

"She'd be fixing supper for you about now, wouldn't she?" It all starts to sound very appealing and it perfectly lampoons the idea of city slickers trying to find authenticity in their lives through the cowboy dream.

There are political overtones and undertones to the play, although they are so subtle they might not exist at all. There are ambiguous lines that could refer to the current political situation in America. These lines resonate beyond the play itself, as when Struther berates himself - "What the hell did you expect?" or when he is finding his present predicament more difficult than he expected, he says, "I do not understand why I'm having so much trouble taming the wild.

I've done this already. Haven't I already been through all this?"

Amidst all the clever humour, there is a lot being dealt with here- the search for some 'authenticity' in life, the loneliness and fearfulness of growing old, and the importance of companionship, "company, some warmth". It's hard not to look at it through an autobiographical filter, with the character Struther and Shepard being the same age.

Shepard has said about Rea that he is "so malleable, he can move in so many different directions" and it is true that Rea gives a wonderful and completely unexpected performance as Struther, from the surprise of the voice to the relish with which he carries out the physical comedy.

Kicking a Dead Horse runs at the Abbey Theatre until 14 April