For much of the past century, Brooklyn was the Rodney Dangerfield of boroughs, known for its blue-collar style, for its funny accent and, of course, for getting no respect.


Then came the brownstone homesteaders and the bohemian pioneers. They turned lunch-bucket warrens in Park Slope, Dumbo and Williamsburg into glamorous destinations, drawing a flood of well-schooled young men and women who were attracted by quaint yet affordable homes, outdoor cafes, bicycle lanes and the neighborhoods’ sometimes self-parodying artisanal, sustainable and locavore ethos.


Brooklyn somehow, against all odds, became an internationally recognized icon of cool.


The sudden physical and cultural transformation has been endlessly debated. Yet to many longtime residents in some of the borough’s unaffected corners — in the rough-edged and timeless Brooklyn that has endured in places like Gerritsen Beach, Marine Park, Sheepshead Bay, Brownsville and East New York — the renaissance is still being watched with amusement, nervousness and even dismay.


In these neighborhoods, rarely mentioned in the city’s tourist literature, some shrug off the re-branding of their home borough as so much tinsel or distant thunder having little to do with their lives, while others worry about being forgotten altogether. Still others express outright resentment that they have not enjoyed the fruits of Brooklyn’s more modish reputation. Shuttered factories in places like Dumbo remind them of lost jobs rather than the expensive lofts that beckon from glossy advertisements.


“I’m glad Brooklyn is making a name for itself and it’s coming up, but if it’s coming up, it should be spread out,” said Joycelyn Maynard, who runs the Stone Avenue Library, a nearly 100-year-old branch in Brownsville, an area struggling with unemployment, foreclosed homes, troubled schools and gang shootings. “I think they pay more attention to parts of Brooklyn that are gentrified.”


“Even in certain parts of Bedford-Stuyvesant you find a cafe table to sit out in the sun,” Ms. Maynard added. “Here, how can you have a cafe where people eat in the sun if they’re concerned about gangs shooting each other?”


In middle-class enclaves like Gerritsen Beach — home to generations of police officers, firefighters and post office workers, where weekends are often for worship and backyard barbecues — fashionable Brooklyn spots like Park Slope or Boerum Hill might as well be a foreign country.


“I enjoy happening places and I would enjoy the restaurants, and I’m glad it’s getting to be on the map,” said Jennifer Avena, whose family roots in Gerritsen Beach stretch decades. “But keep it there.”


The city’s most populous borough remains stunningly diverse. Neighborhoods like Red Hook and Bedford-Stuyvesant mix lives side by side, though not always comfortably. But a look at some of the typical signs of gentrification, income and education shows that sections of the borough are increasingly on divergent tracks.


In the community district that embraces Park Slope and Carroll Gardens, the proportion of households earning over $100,000 rose to 43 percent in 2010 from 28 percent in 1990. In Brownsville and Ocean Hill, the number stayed flat, around 9 percent, while those earning under $25,000 rose to 46 percent from 43 percent, according to a study of household income by Susan Weber-Stoger, a Queens College sociology research associate.


In Williamsburg and Greenpoint, the proportion of residents holding graduate degrees quadrupled to 12 percent; in East New York and Starrett City, it remained 4 percent.


Assemblyman Hakeem S. Jeffries, who recently won the Democratic primary for a Congressional seat that serves gentrifying Fort Greene and Prospect Heights as well as Brownsville and East New York, said: “The poorer neighborhoods were devastated by the collapse of the economy and have not meaningfully recovered.”


“The sidewalk cafes are great,” he said, “but we need a blueprint for employment and housing opportunities that are desperately needed in parts of Brownsville and East New York. We should continue to promote Brooklyn as a trendy destination but cannot forget the bread-and-butter economic issues that many distressed Brooklynites continue to deal with each day.”