It is odd that so much of the national debate over immigration is driven by nostalgia, given how pressingly urgent the subject is right now, and how important to the nation's future.

From certain people we hear the yearning for an idealized era when shop stewards met radical immigrant workers on loading docks. From this group come the researchers who would rather lament the loss of well-paying, unionized, blue-collar jobs than discover new paths of upward mobility.

Others, in the meantime, delude themselves with romanticized visions of the white ethnic immigrant experience of a century ago. They imagine an era in which the huddled masses metamorphosed overnight into patriotic Americans and monolingual English speakers.

None of this really speaks to our current condition. More important, such mythologizing gets in the way of a hard-headed look at how immigrants work and live today. The contemporary literature on immigrants still treats assimilation as if it were a choice rather than an inevitability. And the foreign-born are routinely studied in isolation, as if they were immune to trends in the broader economy and culture.

Fortunately, Jennifer Parker Talwar, a sociologist at Penn State, takes a different approach. In "Fast Food, Fast Track" (Westview, 230 pages, $26), she explores the intersection of today's immigrant experience and the culture of the fast-food industry, which is both a growing source of immigrant jobs and, notoriously at times, a symbol of global capitalism. Ms. Talwar bases her study on interviews and fieldwork done in various fast-food restaurants in New York.

Although the fast-food industry has come in for some strident criticism in recent years, Ms. Talwar is not one of its demonizers. She argues against static images of immigrant isolation on the one hand and fears that fast-food chains will homogenize global culture on the other. She concludes that "the global and the local" move along a two-way street. Rather than being impenetrable cultural bulwarks, restaurants such as McDonald's and Burger King conform to their diverse clientele and to the diverse labor force that serves it.

Indeed, Ms. Talwar finds, immigrants behind the fast-food counter are "go-betweens." They connect mass institutions and new neighborhoods. If older immigrant businesses -- say, German meat packers -- preferred to hire workers from the same ethnic group, because of their shared backgrounds and their vulnerable new social status in the U.S., fast-food companies find immigrant workers desirable for different reasons.

For one, immigrants tend to be young and to take the low-paying jobs willingly, since they see such jobs as merely temporary. More important, immigrants possess "cultural capital" that dovetails with the fast-food industry's marketing efforts. Ethnic businesses traditionally cater to consumers who want goods from the home country, but fast-food chains in immigrant neighborhoods cultivate new tastes among the foreign-born.

Thus while many immigrants view fast-food work as a way to join the mainstream economy and learn English, the fast-food industry itself uses ethnic employees to cultivate new markets. At the McDonald's in New York's Chinatown, the managers make an explicit attempt to attract both new Chinese customers and the thousands of international tourists who traipse down Canal Street each year. As such, they hire young Chinese workers to serve the local clientele and a panethnic, multilingual contingent to serve the tourists. The neighborhood's diversity, then, is reflected in the restaurant's global workforce. And, by necessity, English becomes the unifying cultural element that all employees must share.

Yet fast-food restaurants are not immune to the cultural influences of their employees. At one McDonald's in the heart of a Dominican neighborhood in upper Manhattan, Spanish is not only the dominant language spoken but the only language required for employment. Thus even as its workers assimilate into the standardized fast-food culture, they reassert the culture of their home countries.

Of course, the fast-food industry stops short of being one big happy melting pot. In her even-handed if bland prose, Ms. Talwar describes inevitable tensions and ethnic divisions. She cites Hispanic employees complaining about their Chinese co-workers and West Indians distancing themselves from native-born blacks.

The one bias that seems to permeate all the restaurants that Ms. Talwar studies is an anti-American one. Among the book's foreign-born subjects, "American" is synonymous with the inner-city underclass. Managers who prefer to hire immigrants for their willingness to work hard for low pay tend to write off the native-born blacks, Hispanics and white applicants, who they presume are not as hard-working. To these employers, "American" refers to "partiers" or those who are "not looking ahead." In such a way have immigrant workers redefined the expectations of fast-food employers.

Ultimately, in Ms. Talwar's view, the fast-food industry is not a sturdy ladder upon which immigrants may climb into the middle class. It is just a "stop gap." Workers typically hold other jobs and live with their parents or other family members; in any case, they are not the primary breadwinners in their households. There is no American dream here, she believes, only immigrant aspirations.

Ms. Talwar suggests that immigrants' chances of moving beyond low-wage work depends on the strength of their character and personal networks, and their ability to acquire more training. In the new economy, like the old, it seems, hard work, family and education still matter.