Most people who love Ireland fell in love with the desperately poor, ridiculously friendly and breathtakingly beautiful Ireland.

David McWilliams' brilliant, eminently readable "The Pope's Children" (Wiley, 291 pages, $24.95) is about postmodern Ireland, where the poor are now rich, the friendly are too busy to be as friendly, and that verdant green quilt of countryside is dotted with the vacation homes of wealthy Dubliners who barely use them because they're on holiday in Spain or shopping in New York or Boston.

An economist by training, McWilliams explains the revolutionary, evolutionary change in the Irish: "One hundred years ago, the perfect image of the Irish was a doodeen-smoking, seaweed-picking, bare-footed peasant, smiling in bewilderment for some well-meaning English anthropologist who has just measured the circumference of his cranium," he writes. Today, "a perfect snapshot of the Irish is of a man in an expensive, ill-fitting suit, hands-full, driving or maybe carrying a child distractedly, barking orders down a mobile on an English-owned network."

The book's title refers to the generation of Irish born after Pope John Paul II arrived to a rapturous welcome in 1979. The Irish baby boom peaked exactly nine months after the pope's visit. If one Pole inspired so many Irish babies, it is perhaps only fitting that Ireland, especially its capital, is crawling with Polish workers, as the booming economy has attracted economic migrants from Eastern Europe, Africa and China. Ireland, meanwhile, has become a much more secular country.

This book is indispensable for those who want to understand how Ireland went from being one of the poorest countries in the world to one of the richest in such a remarkably short time, and how this has dramatically changed the age-old question of what it means to be Irish. In a land once known for producing saints and scholars, McWilliams captures the contradiction that is a prosperous, materialist Ireland. McWilliams concludes that despite the materialism, there also has been a revival in Irish culture, especially the language, which used to be forced on a reluctant populace by the government, but is now being embraced by a people who with all their success are perhaps more determined to hold onto something that resides in their souls, not their bank accounts.

Ireland is still a beautiful place with friendly people, but everything has changed. Changed utterly. McWilliams could have called his book "A Terrible Beauty." Alas, that title was already taken.