The subject: bagels. The discussion: far-ranging, from whether there is such a thing as a Chicago-style bagel to who has the best in the city to how chewy the outside should be.

It's not just those foodies who are intrigued by the humble bagel. The simple circular treat seems to give rise to an endless number of topics for contention. Imagine a bagel debate. Discuss: Cinnamon-raisin and chocolate chip bagels are an abomination to the name of Izzy Cohen, retired Lower East Side bagel baker.

Or: The confections sold as bagels at such outlets as Dunkin' Donuts and Dominick's are really something else entirely: round bread with a hole.

Or: Bagels MUST be boiled before being baked to be worthy of the honorable name. (Probably not much argument there.)

One question, though, doesn't seem to have a real answer: Why have bagels always been so identifiably Jewish?

There are many theories.

Jewish historian Irving Cutler surmises that "it goes back to the Eastern European shtetl," and recalls a popular Yiddish song, "Buy My Bagels." "It comes from shtetl days, it was carried over from the old country," he says.

In the somewhat newer old days, Cutler recalls that years ago in Chicago "there was mainly one bagel company, New York Bagels on Touhy. Everybody used to make a special trip to New York Bagels. They were open all night. They'd bake them and bring them to some restaurants. They had a great variety and were very good.

"Bagels used to be basically Jewish, but now they're national. Everybody's eating bagels now," he says. "And why not? They're tasty, good for sandwiches, go great with cream cheese and lox."

His own favorite: "Bagels with jalapenos if I can get them. You can't always get them. I like 'em with cream cheese, sometimes with lox."

Joan Nathan, in her definitive 1998 book "Jewish Cooking in America," gives anther explanation for the Jewish origins of the bagel. She writes: "In Eastern Europe, Jews were particularly careful about their meats, fish, and breads, allowing only Jewish bakers to bake for them."

She goes on to say that she heard an explanation from two Chasidic women of the Beigel family of Cracow, whose family had been bagel bakers for years (hence their name). "They told me about the peddlers, who were religious Jewish men, going out into the countryside and not being able to eat their bread because it had not been blessed. According to Jewish dietary laws, this most holy of foods could not be eaten until after hands were washed and a blessing said. But because clean water was rarely available when they were traveling, the men had to go hungry. So they devised a way of boiling the dough rather than baking it, thus putting bagels outside the category of a traditional bread so that they would not require the ritual handwashing before eating."

In this way, she notes, Jewish bakers became specialists in making bagels.

Nathan finishes her discussion with a lament: "Are bagels today the same as they used to be? Lamentably for us bagel purists, the answer is no. Today bagels are bigger, softer, and there is less of a hole."

Chicago-area bagel bakers might dispute that assessment. Many take great pride in making their bagels the old-fashioned way-boiling before baking, so as to create a chewy outside and soft interior-just as connoisseurs scorn the doughy, bready creations that pass for bagels at some establishments.

Mitchell Cohen, a partner in and manager of New York Bagels & Bialys in Lincolnwood, knows bagels. The store, which has been in the same location since 1967, bakes about 75 dozen a day during the week, more on weekends.

Bagels "used to be Jewish, now they're worldwide," Cohen says. "You don't have to be Jewish to eat a bagel. But probably the majority of our customers are Jewish, or at least 50 percent."

Bagels are "traditionally boiled, and that's how we make them," he says. "Boiling gives the harder crust. Now they have steam ovens where they can make 60 or 70 dozen at a time. It's practical but they don't taste as good."

Surprisingly, Cohen says, the most popular bagel flavor at NYB&B is plain. "Then comes poppy, egg, sesame, then onion," he says. "The other flavors don't sell as good as the mainstays. There used to be only two kinds, plain and salt with poppy seed. Now there's more a mixed variety of people with different tastes. We make a Cheddar jalapeno, sun-dried tomato. But they don't sell as good as the others.

"A lot of people like garlic bagels but they don't like to carry them around" because of their pungency, Cohen adds. "People are pretty bland in what they like, pretty traditional."

The store also carries bialys (a whole other story), which, Cohen says, "started in New York just like the bagel, but it's baked, not boiled, with more of a crusty dough, more like a pizza dough"-never to be confused with the bagel, which is the store's most popular product. Cohen adds they also carry cream cheese and lox, the most traditional toppings.

New York Bagels & Bialys also bakes bagels to sell to other restaurants and stores, such as the whimsically named Dagel & Beli, a year-old East Rogers Park deli that does a brisk business mainly based on its bagels and steamed bagel sandwiches, a specialty.

Taking the concept of customized service to the max, Dagel has patrons fill out a sheet on which they can circle their choice of bagel flavor, "warming preference" (not warmed, steamed, toasted, lightly toasted, etc.), cream cheese flavor and "extras" like alfalfa sprouts, avocado, hummus or peanut butter.

"Everything" (a mix of toppings including poppy and sesame seeds, onion and garlic) and pumpernickel bagels are especially popular, an employee said, with onion quickly gaining on them.

At Kaufman's Bagel & Deli in Skokie, some 44,000 bagels a month come out of the oven-not really so many when you figure it by the day, says Bette Dworkin, the firm's president.

Most popular? Again, plain, followed by sesame, onion and everything.

"Our customers are the old-time bagel people that don't want the frou-frou stuff," Dworkin says. "We don't even make chocolate chip bagels and we don't even sell that many of the blueberry and raisin ones. They're just not for our customers."

Kaufman's, which also includes a full-service deli and bakery, has been named "Best Ethnic Deli" by Chicago magazine several times, she says, and while "we're proud of the whole store," she feels a lot of its reputation is due to the bagels.

"We were a bagel store before bagels were so popular," she says, adding that there's a friendly competition between her establishment and New York Bagels & Bialys for the "best bagels" crown. "Our product is a little bit richer than theirs. It's just a matter of taste," she says.

Of course, Kaufman's bagels are boiled before they're baked, but that's not necessarily the case everywhere, Dworkin says. Some bagels "are not for the purists. In a lot of places it's like white bread in a doughnut shape." Whereas those confections are soft, "bagels are supposed to be chewier, crustier."

Dworkin concurs with most of her competitors that cream cheese is far and away the favorite topping. "But I personally love corn beef on a bagel. We make a lot of those," she says.

At Bagel Country in Skokie, which despite its name is a full-service, kosher restaurant, office manager Janine Orenstein has a pretty precise handle on the bagel outflow. The company makes a minimum of 2,568 bagels a day, sometimes more, she says. Again, out of more than 25 varieties, plain is probably the favorite, followed by everything and whole wheat, which finds favor with "people who are trying to eat healthy," she says. A specialty of the house is the Jerusalem bagel, which is softer and sweeter than the average bagel and is not boiled but baked.

"All of them sell out," Orenstein says, "poppy, sesame, even the sweet ones sell out."

B.B's Bagels, a kosher establishment in Chicago's West Rogers Park neighborhood, also joins in the plain parade, a spokesperson says, followed by whole wheat, sesame, poppy and everything. B.B's bakers turn out 300 to 500 bagels a day.

Einstein's Bagels has a number of locations and the popularity of any one kind varies from neighborhood to neighborhood, therefore from store to store, says the manager of the Evanston location, who calls herself simply Michelle. That location sells about 900 bagels a day; they're baked on the premises.

"The most popular varies from store to store," Michelle says. "In this store it's plain, asiago cheese or raisin. In different parts of town there are different types of people, different nationalities, different religions"-hence different bagel preferences. But one constant remains: "Cream cheese is the most popular topping."

"Lots of people are doing bagel sandwiches, like egg sandwiches on a bagel," Michelle says. "Everybody is coming up with breakfast bagels, even Starbuck's has 'em."

Jewish Chicagoans have a variety of thoughts on bagels. Judy Teller, director of the Lewis Summer Intern program at the Hillels of Illinois, thinks heaven is a pumpernickel one. When her husband goes out to buy bagels, he always remembers to buy one of her favorites, she reports. Cream cheese and lox make it even better.

Tami Warshawsky, a publicist and Jewish community volunteer with many organizations, strikes a dissenting note. "I'm very health conscious, and since the average bagel has over 400 calories, I really try and avoid bagels," she says. "But if I do eat them, my favorite is sesame if I'm not thinking about being healthy. If I am, I'll have a 12-grain bagel from Bagel Country. But my kids could turn into bagels."

Todd Winer, communications director for the American Jewish Committee in Chicago, favors the everything with cream cheese. "I'm not a big plain bagel eater," he says. But his son Abe, age 4, is. "He has a pretty short list of foods he'll eat," Winer says, "and a plain bagel with cream cheese has made the cut."