TWO SIDES OF IRELAND; LYRICAL LOVE STORY INTERTWINES THE MUNDANE AND SPIRITUAL.

Byline: Bernadette Murphy Special to the Daily News

``As It Is in Heaven''

by Niall Williams 

(310 pages, Warner Books; $23.00)

Our rating: Three and one half stars

As the daughter of Irish immigrants, I spent my childhood listening to stories told in the traditional Celtic manner. Luxuriant, taking all the time in the world, such stories are filled with quips from shopkeepers and eccentric neighbors, women who see banshees, and the unmistakable voice of God. These mythological histories are rich in ancient spirituality; they are a place where fate conspires with human will, where pain is the portal through which un-thought-of wonders arrive, where dreams are portentous, and food magical.

What a joy, then, to open Niall Williams' second novel, ``As It Is in Heaven,'' a love story told in this uniquely Irish manner. As with his first novel, ``Four Letters of Love'' (Farrar, Straus, Giroux, 1997), Williams invokes the kind of Celtic folklore in which the spirit realm is contemporaneous with the material world and the mystical elements of life are little more than imagination stretched to encounter the metaphysical.

Williams' previous novel tapped similar love-and-mysticism territory, earning him rave reviews and an appearance on the ``best of'' lists by The New York Times and Publishers Weekly. In ``Heaven,'' the same questions about the spiritual nature of love give the story its texture. Philip Griffin and his son, Stephen, are in the shadow of loss that began 20 years earlier when a drunken driver claimed the lives of Philip's wife and daughter, Stephens mother and sister. The two have been irreparably stunted by that loss. Their lives stretch before them with little hope of rebirth until Stephen - now 28 years old and accustomed to his barren life - meets Italian violinist Gabriella Castoldi.

The romance is unlikely: Gabriella, like Stephen, has been so damaged by early loss as to believe love unthinkable. But that's the beauty of fable: its power to make the impractical suddenly burst with possibility by inverting our disbelief. Williams accomplishes this feat with lyric gracefulness and precise use of metaphor.

The plot itself is animated by the mystical. When Stephen realizes he's in love with Gabriella, for example, he doesn't tell his father. Philip, however, detects his son's state of lovesickness by playing chess with him, using his son's movements as a barometer of the risk his heart has incurred. In order to help Stephen through what he can only imagine as heartache, Philip, now dying of cancer, makes a deal with God. He wants to live until the love affair is resolved.

In the ensuing romance, the lives of all people - not just the lovers themselves - are transformed by the budding passion. Nelly, the greengrocer, notes Stephen's hesitation and concludes that a ``man like that needs plums.'' She proceeds to bring out his reclusive heart through fruits, vegetables, a haircut and a bit of sunshine. In such small acts of kindness, Williams illustrates humanity's underlying unity and our ``desperate need to believe love like God's exists on earth.''

True, the plot of this novel is familiar: love overcomes hardness, compassion conquers pain, the life of the son eclipses that of the father. But don't let the simplicity stop you from seeing the true beauty of this work. With skillful writing and great insight, Williams takes the ordinary details of life and lights them with intelligence and depth. Like when Philip, a retired tailor, tells us ``you can know a lot about a man when you are measuring him for trousers.''

Though the characters of Stephen and Gabriella don't rise to the same level of complexity as Philip, you are swept up in the fable enough to forgive their relative flatness. Likewise, the novel is not without corny moments, but when in a fairy tale, who cares?

Of the young lover Stephen, Williams writes, ``He had a surging sense of the absurd anachronism of romance, of its obsolete currency in the world, as though it was credible only in fables.'' This story, like a fable, is undeniably far-fetched. But Williams' prose reminds us of what's right and solid and beautiful in life. The emotion of love, as conjured in Williams' writings, will make believers out of us all - however briefly.