BOOK REVIEW / NONFICTION : Exploring the Catholic Soul of Europe : THE SIGN OF THE CROSS: Travels in Catholic Europe <i> by Colm Toibin</i> ; Pantheon $24, 304 pages

You might say of Colm Toibin that there’s not a religious bone left in his body. An altar boy in County Wexford, he must have tumbled onto something upon noticing that his father would occasionally depart the family rosary with a fit of the giggles. Toibin lost his faith at 14 and went on to become a nonbelieving member of the Dublin literary intelligentsia, more secular European these days than strictly Irish.

Well, you can take the lad out of the Irish church but not quite the Irish church out of the lad, however up to date. More exactly, when you do take it out, the hole twitches. In “The Sign of the Cross,” Toibin travels about the Catholic parts of Europe interrogating its varying devotional manifestations. His exploration is touchy, skeptical and faintly susceptible; and all the more irritated because of it. Hole, indeed: the book suggests nothing so much as a tongue curling to prod compulsively at a cavity.

For his exploring tool, Toibin uses astonishment. Sometimes it seems a journalistic convenience. Having lived in Spain for several years--two of his books are based on his time in Catalonia--he dons an excessive naivete to describe the fervor of the Holy Week processions in Seville. A writer of considerable poetic gifts, Toibin’s descriptions are enlivening. But his bewilderment at a socialist city turning out to greet the elaborate floats of the Virgin feels put on. It invokes for Spain a dialectical rigidity that belongs to northern not to southern Europe.

His shock at finding in a church the gravestone tablet of Gen. Queipo de Llano--who butchered Seville’s Republicans during the civil war--also seems forced. All kinds of horrible people lie beneath Catholic churches; Toibin must have been a distracted altar boy not to have picked up that Christianity’s purpose is to wash dirty hands, not clean ones. The scandal was that the Seville clergy supported the general when he was alive, not that it buried him when he was dead.

Traveling to Poland, Croatia and Bavaria; observing the pilgrims at Lourdes, Santiago de Compostela and his own Irish mountain Croagh Patrick; and casting a cold eye here and there--though it sporadically warms--on Pope John Paul II, Toibin will sometimes weaken his provocative observations by draping too much over a dramatic question whose answer he knows.

He has a wonderful account of climbing Croagh Patrick in an Irish crowd, but why make a point of the local bishop waiting at the bottom to bless everyone afterward? Surely he is aware that saints climb, bishops stay below and that not only a mountain, but the Church as well, places saints higher. In a thoughtful account of his feelings about the Pope--he detests his authoritarianism and seems drawn by his spirituality--he tells us that John Paul’s benevolent regard stiffened during his Irish visit when a woman approached him impromptu out of a crowd. Toibin implies arrogance; why not a carnal reflex? A man in a crowd shot John Paul, and the body remembers.

Toibin’s foreshortenings shorten his range, somewhat, but when they drop away we encounter a more profound and provocative unease. The two best sections are set in Poland and Croatia. In the former Toibin finds, as he never did in Ireland, a nation whose Catholicism--after the struggle against communism--has become an active national and political identity, even for the young. The sight of long lines of young people queuing up for confession during Easter week puzzles and disturbs him. He could have strayed from Harvard into a student chapter of the Christian coalition.

In Croatia, Catholic nationalism--prayer in the streets and weapons in the sheds--presages much more than unease. Ireland is in the Common Market, and one might call Toibin a member of the Common Market avant-garde. It was only 70 years ago, though, that there were guns in County Wexford sheds, as well.

From such shadows, he turns with wicked joy to interviewing English Catholics. Writing about the English is an Irish delectation, and Toibin is particularly pleasurable with Ann Widdecombe, a junior minister in the Conservative government and a recent Catholic convert. Her conversion, like that of a number of other English on the right, seems to have been mainly a matter of walking away from the “laxness” of the Church of England.

Actually, Widdecombe, who seems to have learned starchiness as well as politics from Margaret Thatcher, has not so much converted to the Church as marched in like some medieval prince at the head of his battalions. Hers is not to be confused with the Catholicism of the Liverpool Irish. She has little patience with transubstantiation, Purgatory or the cult of Mary. (At an impasse with the priest who gave her instruction, she went straight to Cardinal Hume--a junior minister--who reassured her that 100% belief was not required.) What about the saints? Toibin asks. “They hardly get a look in,” Widdecombe snaps.

Cardinal Hume, do you remember Henry VIII?