Curtis Crawford, a black man, owes part of his success to affirmative action - a process that a decade ago denied Allan Bakke, a white man, admission to medical school.

Both men are symbols of the evolving struggle for racial equality in America.Crawford, who runs a $3.5 billion annual program for IBM, says affirmative action played a big part in his rapid rise to high-powered executive with one of the nation's corporate giants. But he says hard work and personal sacrifice were essential as well.

In the 10 years since the Supreme Court redefined the concept in the case of Bakke, a would-be medical student, affirmative action has become even more of a fixture in American society - in private enterprise, in law and medical schools, in local police and fire departments.

But preferences based on race and gender remain highly controversial, particularly fixed quotas that spark heated debate over "reverse discrimination."

The Supreme Court on June 28, 1978, ruled that Bakke, then a 37-year-old engineer, wrongly was denied admission to study medicine at the University of California at Davis.

The justices, by a 5-4 vote, said a fixed quota for racial minorities at the medical school unlawfully excluded Bakke because he is white. He had been passed over while less-qualified applicants were admitted under a special program.

But a different 5-4 alignment said colleges may consider race as one factor in deciding who gets admitted.

The Bakke case galvanized public opinion as have few legal battles in the nation's history.

But it marked only the start of a continuing debate on how far the nation should go to redress past discrimination.

IBM executive Crawford started with the company 15 years ago, about a year out of college.

Today he is a vice president at the company's plant in Montvale, N.J., in charge of marketing its line of new personal computers, the Personal System II. Yearly sales are around $3.5 billion.

Crawford, son of factory-worker parents and reared in what he describes as the poor part of Joliet, Ill., is no friend of racial quotas.

"I've never been in favor of specific numbers. That's not the way to achieve equality," he said.

He is a strong supporter of American institutions that demonstrate steady commitment to equality by providing opportunities for minorities and women to get ahead.

"We believe affirmative action makes good business sense," he said. "The company also is fulfilling its social responsibility."

Crawford is a symbol of the boon affirmative action can be to middle class blacks, Hispanics, other minorities and women.

On the other hand, civil rights leaders say it has failed to ease spiraling unemployment that helps hold the nation's inner cities in the grip of poverty, despair and drugs.

The Reagan administration has fought a losing rear-guard battle for the past eight years to restrict back pay or other compensation in suits based on claims of affirmative action violations to individuals who can prove they were victims of bias.

The nation's highest court rejected that argument in a series of cases. But fragmented voting among the justices and the advent of new Reagan appointees on the court could mean an uncertain future for affirmative action.

In recent rulings, the court has embraced preferential treatment for wom-en and minorities in hiring and promotion. It even has endorsed quotas, as long as they are narrowly tailored to overcome proven past discrimination and do not trammel unnecessarily the rights of white males.

American business also has demonstrated support for affirmative action, particularly big corporations and industry leaders like IBM.

Bakke's alma mater is one institution proud of its civil rights record and willing to discuss it openly.

"We have actually a diverse class. We think it's of great academic benefit," said Dr. Hibbard E. Williams, dean of medicine at the University of California's Davis campus.

After the Bakke ruling there was a drop in minority enrollment for five years at Davis. Minorities seemed to believe the school was not for them even though college officials had defended quotas all the way to the Supreme Court.

Blacks, Hispanics, Asians, American Indians and other minorities comprise nearly half of the enrollment at the medical school today. There is no fixed quota, but recruitment of minorities is intense and is intended to produce a model of the diverse racial make-up of California.

"Students in general learn a great deal from their own colleagues," says Williams. "They get a more accurate view of life out there - from alcoholics to the destitute, aged individual who is demented to the wealthy businessman with a heart attack."

The sentiment is hardly universal.

Officials at AT&T recently were embarrassed by a white supremacist group that called for the telecommunications giant to phase out its affirmative action program.

Ironically, some resistance to preferential treatment is coming from black executives and professionals, seemingly the leading beneficiaries of these programs.

On the positive side, one measure of growing equality in at least some sectors of American society is the number of elected black officials.

There were only 200 holding office in 1965 - a time when exuberance over the civil rights movement was at its peak. By 1986 that figure had grown to 6,500.

Yet some controversial issues remain unresolved.

While there may never be another case like Bakke's to rivet the nation's attention, key aspects of affirmative action and alleged discrimination will continue to be argued before the Supreme Court.

The justices will examine the power of local governments to require minority participation in public works projects.

The court also has said it will explore anew the right of white males to challenge court-approved voluntary affirmative action agreements between public employers and minorities.