St. Denis, France - Raouf Ben Halima, 39, sleeps on his side, never on his stomach. He enters the bathroom leading with his left foot but puts his pants on leading with his right. Instead of using a fork when he eats, he uses his index finger, middle finger and thumb.
Mr. Halima is a member of the Tablighi Jamaat, or Preaching Party, a global army of Muslim missionaries helping to expand their religion and reinforce their faith. They believe that emulating the habits of the Prophet Muhammad is the surest way to restore Islam to its intended path.
So Mr. Halima and his associates shave their upper lips but let their beards grow. They wear their pants or robes above the ankle because the prophet said letting clothes drag on the ground is a sign of arrogance.
"Halfway between the knee and the ankle is best," Mr. Halima explains, sitting amid stacks of religious tracts in his small home.
His comments, made recently to a reporter during conversations about the growth of militant Islam, offered a rare window on the beliefs of a group that is unsettling to many here. The Tablighi are one of the primary forces spreading Islamic fundamentalism in Europe today, and many young Muslim men pass through the group on the way toward an extreme, militant interpretation of the religion.
Beyond that, little about the group is known.
The window Mr. Halima offered was open only briefly: he spoke only about his own experience and refused to accompany a reporter to France's main Tablighi mosque for fear of being seen breaching the sect's strict rules of secrecy.
European terrorism officials who follow Tablighi closely say they know many cases in which terrorists have emerged from the movement, but they say they have never been able to penetrate the group sufficiently to prove that it plays any direct role. "It is definitely fertile ground for breeding terrorism," said a French intelligence official who has traced many militants' religious awakening to their membership in the movement.
Zacarias Moussaoui, the only person to be charged in the United States in connection with the Sept. 11 attacks, was once a Tablighi adherent in France. Hervé Djamel Loiseau, a young Frenchman who died fleeing the 2001 American bombardment of Tora Bora in Afghanistan was, too. Djamel Beghal, an Algerian-born Frenchman and confessed Qaeda member recently convicted in Paris for plotting to blow up the American Embassy, was a Tablighi follower in the French town of Corbeil a decade ago.
The movement got its start in the mid-1920's when a man named Mawlana Muhammad Ilyas, disturbed by distortions of Islam in the face of India's predominant Hinduism, began preaching in the poor neighborhoods of Delhi. It is now considered the largest Muslim missionary movement in the world. Its yearly November gathering in Raiwind, Pakistan, may be second only to the hajj in drawing Muslims.
On the Continent, the group's main base is in France, where most of its adherents are North Africans, according to experts watching it. Introduced here in the early 1960's, it grew quickly during the 70's and 80's, one the country's few Islamic organizations at a time when Europe's economic slump had left many Muslim immigrants unemployed.
"They were the first Islamic movement in France and the rest of Europe to target young people who were destabilized," said Gilles Kepel, author of "The War for Muslim Minds." "They targeted young people who were lost in their identity, were involved in delinquency, drinking, petty crime, and proposed reorganizing their life."
Mr. Halima, a senior Tablighi activist who once spent a week with the movement's governing council in Pakistan, estimated that 50,000 to 100,000 people had passed through the Tablighi movement in France and that there were about 5,000 active members. But there is no way to confirm these figures.
Shortly after Islam's twilight prayer here, bearded and robed men stream out of the Tablighi's central mosque in France, a small two-story house freshly painted eggshell white not far from Mr. Halima's home.
Their approach to idle young men in this working-class town on the northern outskirts of Paris is usually the same: they offer a handshake, touch their hand to their heart, and ask, "Do you go to the mosque?"
Only occasionally do the missionaries return to the mosque with someone in tow.
Mr. Halima was once such a person. Now a cheerful proselytizer who publishes pamphlets promoting the Tablighi Jamaat and other aspects of fundamentalist Islam, he took a path to the Tablighi that may well be typical of European recruits. He said he was born to a Tunisian father and an American mother who divorced and moved to Britain when he was a child and brought up with no particular religious training. He began to seek spiritual sustenance by the time he left adolescence.
At 16, he met a Tablighi member in southwest London and soon attended a three-day mosque retreat. Before long, he was joining outings to visit other mosques across Britain as a missionary.
The Tablighi's obligation includes proselytizing 3 days every month and 40 days once a year. Every devoted Tablighi is also expected to make one four-month trip to Pakistan to study at the organization's central mosque.
"The Tablighi only care about bringing people back to Islam," Mr. Halima insisted. "We are not political." But he said Tablighi-sponsored trips to Pakistan put young men in contact with fundamentalists of many stripes, including adherents of Salafism, a fundamentalist school of Islam whose radical fringe advocates war against non-Muslims.
Abandoning the Tablighi during such trips is discouraged, he said, but there is no stigma for those who wished to leave for more radical groups later.
He acknowledged that young men wishing to migrate from the Tablighi to more militant forms of Islam had no trouble finding their way. "Everyone knows which mosques attract Salafists, and if you go and ask, it's easy to get into the jihadi network," he said.
He said most people touched by the Tablighi eventually moved on to practice a more moderate form of Islam, but of the hundreds that remain engaged in fundamentalism, he estimated, half are recruited by Salafists.
"The Salafists are very aggressive," Mr. Halima said, adding that they are growing faster than the Tablighi.
In the Tablighi's central mosque here, across a park from the 12th-century basilica where many of France's kings are interred, a young man with a long beard and a long stick watches over the tiled front room where visitors remove their shoes and those coming for prayer perform ablutions in communal sinks. In the small, carpeted worship room, the only decoration is a lone shelf of religious books and a row of clock faces showing the times of Islam's five daily prayers.
A group of bearded men sit on the floor, talking quietly beside a low wooden box that serves as a desk. Seeing a visitor, one of them gets up and introduces himself, whispering so as not to disturb another man praying in a corner. "Happiness is inside us all, you only need the right glasses to find it," he begins. "Those glasses are faith."