But beyond the glow of this sudden efflorescence that made Ireland the fourth most-affluent country in the Organization for Economic Cooperation and Development, a housing bubble had begun to form. Low interest rates, a wave of inward immigration and a bank lending spree drove housing’s share of the economy to 14 percent, the highest in Europe, from 5 percent, according to research done by Finfacts, a financial Web site that analyzes the Irish economy.

Developers like Mr. Dunne became multimillionaires and  much like the hedge fund and private-equity elite in America  became visible public and cultural figures. They were living large in a country just coming to grips with its ability to show a little swagger.

Ireland’s policy makers, like their counterparts in the United States and Britain, were seduced by record tax inflows and a full-employment economy. They paid little heed to the lonely voices that warned of the crash that finally came over the summer, when interest rates in Europe began to rise. Banks that had steered more than 60 percent of their loans toward property stopped lending, and asset values plummeted.

“We have repeatedly warned that the government’s housing policy was extremely dangerous,” said John Fitz Gerald, an economist at the Economic and Social Research Institute, a leading policy center in Dublin, who has long urged that the government stanch housing demand by raising taxes. “You will now see unemployment going to 10 percent and we will experience a sharp drop in output.”

He shakes his head and sighs: “This was predictable, but the government just did not deal with it.”

BY wide consensus here, two events have come to define  both culturally and financially  the sweep and excess of the Irish property boom. Both revolve around Sean Dunne.

In July 2005, Mr. Dunne paid 379 million euros for a seven-acre plot in the exclusive Ballsbridge neighborhood of Dublin and promptly announced that he would tear down the two luxury hotels on the site to build a high-end commercial and residential development.

That deal amounted to 54 million euros an acre, one of the highest amounts ever paid for land in Europe. His subsequent architectural plan featured a soaring Dubai-like office tower cut in the shape of a diamond that anchored a futuristic community of expensive houses and glamorous shops, and the price tag of one billion euros shocked Dubliners with its gall and ambition.