Jerusalem, Israel - The newly opened Kosher Gym in Jerusalem offers prayer books instead of magazines at its juice bar, and bearded men listen to Talmudic interpretations on earphones as they exercise.
In an Internet chat room, messages about Outlook and Microsoft pop up in Yiddish. At upscale kosher restaurants, men in black hats and sidecurls, accompanied by wives in wigs and long dresses, sip fine wines.
If that's one face of the haredim - ``the God-fearing,'' as Israel's ultra-Orthodox Jews refer to themselves - another is the young hotheads who torch clothing stores in their neighborhood for selling ``immodest'' attire, and hurl bleach at women who wear it.
From cell phones to Stairmasters, from women's rights to Hebrew slang, the outside world is seeping into the cloistered haredi community and plunging it into a tug-of-war between a tentative embrace of modernity and fierce resistance.
Similar communities are replicated across the world, with the Bible and Jewish law central to their lives. The difference is that in New York, London or Sydney they have little impact on society around them. In Israel, the relationship is very different, and often bumpy.
Haredi political parties have often held the political power to make or break a government. The men spend their lives in prayer and study, subsidized by taxpayers who can't see why they don't just get a job. Every secular Israeli, male and female, must do military service, the great leveler in a country of immigrants from east and west. But haredim are exempt.
They belong to a religious power structure which at various times during Israel's existence has managed to ban public transport on the Sabbath, grounded El Al, the national airline, on holy days, and has absolute control of all Jewish marriage and divorce. This power was reinforced last month when 12 of 15 new rabbinical court judges were recruited from the ultra-Orthodox - a move that caused a furor among secular Israelis who had hoped more moderate judges would join the court.
Haredim tend not to take firm stances on the big issue confronting Israeli society - war and peace with the Arabs. But their birthrate of seven children to a family is a force in Israel's demographic race against the Palestinians.
As Israeli society grows more pluralist, advancing the rights of women and gays, the haredim cling to the old ways, and sometimes the clash is extreme; in 2005, when Jerusalem held a gay pride parade, a protesting ultra-Orthodox Jew stabbed and wounded three marchers.
Yet reality is forcing change in many areas.
The haredim, many of whom once opposed Zionism as a blasphemous pre-empting of the Messiah, have largely made their peace with the Jewish state.
At the same time, election results have enabled coalition governments to be formed without the haredim. The sidelining of haredi parties in recent years has led to cutbacks in their subsidies, and haredim are beginning to trickle into the job market.
``There are many changes coming in the haredi world, because you can't offer only one lifestyle, you can't offer only one life opportunity for a whole range of abilities and spiritual levels. You'll lose too many that way,'' said Jonathan Rosenblum, a haredi columnist.
The word haredi is an umbrella term for a variety of groups, each following its own ancient sages and living rabbis.
It broadly means anyone who takes the maximalist approach to Jewish law, and follows a lifestyle whose most visible characteristics are unlikely to change soon.
Haredi neighborhoods in Jerusalem or the Tel Aviv suburb of Bnei Brak feel like 18th century European ghettos: men in long black coats and large fur hats called streimels; women in shapeless dresses covering their wrists and ankles, wrapped in scarves or wigs because they shave their heads when they marry.
In Mea Shearim, Jerusalem's largest haredi neighborhood, cars are banned on the Sabbath and toddlers ride tricycles down the middle of the street. In synagogues, men press their lips to the words of an open Torah scroll.
Last week, on street corners and empty lots in Mea Shearim, the ultra-Orthodox burned bread and other leavened foods in large communal bonfires in preparation for Passover, commemorating the flight of the Israelites from bondage in Egypt.
Haredi households shun TV, and haredi rabbis have ruled that only cell phones without Internet access are permissible.
Israel's haredim number an estimated 600,000 - nearly 9 percent of the population and growing fast. Jerusalem, the city at the center of the Arab-Israeli conflict, is now one-third haredi and has its first ultra-Orthodox mayor.
The haredim view themselves as Judaism's lifeline, dedicated to preserving the religion in its purest form. The past, not the future, captivates the haredi heart, dating back to the giving of the Ten Commandments on Mount Sinai.
``Our purpose in this world is just to come closer to God, as close as we can,'' said Abraham Kalman Riter, a seminary student in Jerusalem. ``We're going to keep our fur hats and our streimels and our long frocks, because we have one goal and nothing's going to deter us from that goal.''
But modernity is creeping in.
A recent study showed that more than a third of the homes in Bnei Brak - the Tel Aviv area's main ultra-Orthodox enclave - have computers. Haredi newspapers which once confined themselves to religious issues now write on topics such as child psychology. New schools are training haredim to work.
Israel's haredim used to be mostly European and Yiddish-speaking, but today one-third are from Middle Eastern countries, and the lingua franca increasingly is Hebrew, peppered with Israeli secular slang.
A haredi comedian known as David the Impersonator slays young ultra-Orthodox audiences with such one-liners as, why does a miser pray quickly? Because heaven is a long-distance call.
In the Hebrew Web forum B'Hadrei Haredim, or In Haredi Rooms, a surfer announces his family-arranged engagement to a woman he has known for 15 hours. Is 15 hours enough? he is asked. ``I think yes, absolutely,'' he writes.
In another chat room, women trade tips on where to find a good wig, or a job in computer programming.
Still, all these innovations have their limits. The Kosher Gym has separate hours for men and women, and at David the Impersonator's shows, the men in the audience stand in front and the women in the back.
Women's rights weigh heavy on the debate about modernity. The most startling recent example is what some have called an Israeli Rosa Parks story - a group of Orthodox women who refused to sit at the back of a bus on gender-segregated routes catering to the religious community.
Miriam Shear, a 50-year-old Canadian woman visiting Israel for religious study, said she was kicked, slapped, pushed onto the floor and spat upon by a group of haredi men for refusing to give up her seat. Her case is cited in a petition to the Israeli Supreme Court submitted by a group of women, including Israeli-American author Naomi Ragen, who said she, too, was verbally abused on one of the segregated lines.
``The Jewish people have never had this kind of thing. We're around for thousands of years. What did they do in Europe, put women on the back of the wagons?'' Ragen said in an interview.
A rabbinical ruling can apply to areas as mundane as wigs.
In 2004 rabbis decreed that wigs imported from India were unacceptable because, they said, some of the hair may have been used in Hindu ceremonies involving idol worship.
Indian wigs supply 70 percent of Israel's harediyot - ultra-Orthodox women - and they had to make do with hats and scarves until the rabbis devised new criteria for ``kosher wigs.''
Economics are a much more pressing issue. Because of the cutbacks in subsidies and a tight job market, about half the community is thought to be living in poverty. Few rabbinical rulings have caused as much dismay of late as a ban on post-secondary degrees for women - the main breadwinners in haredi society because so many of the men study Torah full time. The move is liable to push the haredim even deeper into poverty.
The ruling may have been driven by hard-liners who blame an apparent rise in the haredi divorce rate on women entering the workplace.
Austerity is now in vogue. A radio reality show features 13 religious families competing at cutting their expenditure on food, utilities and clothes. Whoever pinches the most pennies wins a household appliance worth $4,500.
The better-off, however, can be seen enjoying the fruits of modernity as they sip cappuccino at outdoor cafes or shop for sweaters (black only) at trendy secular stores.
Media and the Internet have rubbed some of the edges off the hostility secular Israelis feel toward haredim. Through movies such as the acclaimed ``Ushpizin,'' about a haredi couple's desperate battle with poverty, the public which so resented those subsidies to haredim now sees the effects of withdrawing them.
Still, the average Israeli tends to be skeptical of the haredi argument that a life of Bible study is as great a service to the state as joining the army, or that the growth and vitality of the haredi community is the most powerful riposte to Hitler's genocidal schemes.
William Glaberson, an ultra-Orthodox Jew who heads the physics department at Jerusalem's Hebrew University, says he's perplexed by the belittling of Bible study.
``Do you know how many colleagues I have who learn Ugaritic syntax and they spend their time writing esoteric papers on dead languages, and all kinds of things like that, and they're not considered parasites?'' he said.
``It's kind of a joke. What do they contribute to society?''