In the mid-1950s, when E. Franklin Frazier examined "the myth of black society . . . " in his book, "Black Bourgeoisie," the Howard University sociologist set black America on its ear.

Commenting upon the vagaries of the black middle class in Washington, Frazier made many derisive references to debutante balls, cotillions and large sums of money spent in playing poker. While Frazier did not even analyze the phenomenon in historical context, his book still became the standard work on the black middle class.

Now finally, Frazier's book has been supplemented by "The New Black Middle Class," written by University of Maryland sociology professor Bart Landry.

So what's new about the black middle class?

Well, numbers for one thing. According to Landry, in 1960, just 13 percent of blacks, compared with 44 percent of whites, were in the middle class. By 1970, the proportion of middle-class blacks doubled -- to 27 percent.

"While this was far below the 1 out of 2 level of whites in 1970, the gain experienced by the black middle class during the 1960s exceeded their total increase during the previous 50 years," says Landry.

He traced that explosive growth to the simultaneous convergence of opportunities generated by the civil rights movement and the prosperity of the 1960s. Of course, the fortunes of the black middle class also were abetted by the policies of President Lyndon Baines Johnson.

Landry also tries to develop a newer school of thought for defining who is in the black middle class. In contrast to some scholars who use income as the gauge of who is in the black middle class, Landry rejects income alone as an "arbitrary" definition, and includes occupation, saying only white-collar professionals, administrators, sales and clerical workers are middle class. That's because he thinks white-collar job security and mobility give this group a more solid economic position in the wider society.

Looking at life style, Landry notes the trend toward black suburbanization had reached 6.1 percent by 1980. But he says that this not only falls far short of the proportion of blacks in the nation, but has largely occurred with the same racially discriminatory channeling of black residents into selected localities that characterized central cities.

While advocating educational measures to lower the high dropout rate of inner-city black youth and economic supports to lift sagging college enrollment to help propel poor youths into skilled jobs and the middle class, he doesn't deal extensively enough with how blacks moving outside of inner cities, leaving an absence of successful role models for emulation, have contributed to the negative plight of the underclass. Indeed, more action strategies to help reverse community and attitudinal problems would strengthen this otherwise comprehensive book.

But Landry also points out some sobering realities about the black middle class. Using surveys of middle-class blacks and whites, he shows that middle-class blacks earn less money and must depend on two incomes. In the mid-1970s, when one full-time income was enough for most white middle-class families, black families depended on two. Also, he found blacks own fewer consumer goods, take more modest vacations and have less savings than middle-class whites.

Indeed, during the 1970s and 1980s, middle-class blacks found themselves falling farther and farther behind as national prosperity declined. Between 1974 and 1981, for example, the average income of black professionals increased by only 38.7 percent, compared with 66.7 percent among whites. With the election of Ronald Reagan, that decline has continued.

Concluding that the future of the new black middle class faces uncertain growth, Landry writes, "Occupational, income and housing discrimination, fueled by both economic uncertainties and the conservative policies of the Reagan years, is still a part of life. The momentum of the late 1960s, though not completely lost, awaits more prosperous times and a renewed commitment to affirmative action in the country as a whole."

The conclusion of Landry's book raises the fear that eight more years of a conservative administration could erode the ranks of the black middle class even more: "The new black middle class," he says, "although real and still growing, is finding the American Dream a little bit tarnished."