WHEN the first thing you hear about a play is that it has to do with sexual abuse and the priesthood, it can be hard to stifle a yawn. Which is very unfortunate for John Patrick Shanley's play Doubt, because it is a gripping work whose focus is not any act of impropriety itself, or even the wrongdoings of the Catholic church (which have been much examined throughout the arts). Rather it focuses on the questions such wrongdoing and a lack of hard evidence raise amongst its cast.

The question here is how can you ever really be sure?

Set in a Catholic school in the Bronx in 1964 and against the backdrop of the civil rights movement, the school principal Sister Aloysius Beauvier (played by Brid Brennan) has suspicions that the young hip priest Father Brendan (played by Aidan Kelly) is carrying on an inappropriate relationship with a young black boy at the school.

She immediately embarks on a campaign to remove Fr Brendan from the school and her rigid certainty that a wrongdoing has taken place (we never know if one has) is stoked by her dislike of the younger, more modern priest, which makes one wonder how much of her certainty is haughty self-righteousness.

But that's where both the young nun Sister James (played by Gemma Reeves) comes in, and Mrs Muller, the mother of the boy in question, comes in.

Reeves's gullible young nun provides much light relief and gives Fr Brendan the benefit of the doubt, but Mrs Muller casts a much darker shadow of doubt on Sister Aloyisius's ambitions to remove the priest from the school. She reveals her young son's homosexuality, a difficult home situation and a desperation to keep her son in a good school, even if it is in the care of a predatory priest.

The four characters work well together but are so purpose-written in their types . . . Sister James' naivety; Sister Aloysius' cynicism . . . that they can seem a little too much like vehicles for the play. But they are superbly acted and draw out the argument very nicely. They also highlight just how easily our beliefs can come asunder when a little doubt is applied.

This play won a Tony Award for its run on Broadway and a Pulitzer so there is no doubting its quality as a play.

Director Gerry Stembridge has done a good job here too, but he has fantastic raw materials to work with in his cast. There is plenty of humour too in witty asides, as might be expected of Shanley (he won an Oscar for his screenplay for the 1988 film Moonstruck).

What is most noticeable about this play is its pace. It gallops along with no interval and yet it does not feel rushed or compressed into the 90 minutes it takes.

By the end, we are left with doubts of our own, but this play would be a cop-out if it were to leave you feeling any other way.

Doubt continues at the Abbey Theatre until 25 November