Today's lesson is that there is no such thing as affirmative action. There is no such thing as being black or being white.

In the view of Lonnie Edmonson, there is only multiculturalism. Based on his personal and professional experience, those who learn not to highlight differences but to appreciate them will go furthest in the business world.

Edmonson has some reason to believe this. He spends most of his time teaching it to the senior vice presidents, payroll clerks, accountants and secretaries of the Federal National Mortgage Association -- known as Fannie Mae -- the country's largest investor in home mortgages.

Through a program with H.D. Woodson Senior High School in northeast Washington, Lonnie Edmonson has embarked on a mission that has helped deliver 62 students to college and led hundreds of Fannie Mae employees to some understanding of cultures they know little about.

"People who are going to be the most successful in the next generation are those who can interact in a professional environment ... with Latinos, Asians and a whole new wave of European immigrants," said Edmonson.

Edmonson's goal is twofold: First, it is to help black youngsters prepare for college and the professional world of business by using the multimillion-dollar resources of Fannie Mae -- scholarship money, summer internships, prep courses on applying for financial aid, the opportunity to rub shoulders with the brass at a large corporation.

And, it is to prepare Fannie Mae for the future by exposing its employees to other cultures, linking them with the Woodson students as mentors. The company's work force is already fairly diverse -- almost 40 percent belong to minorities, and 58 percent are female -- but it promises to look even more diverse over the next decade or so.

Some companies would call this experience "diversity" training, a hot new management tool that attempts to help employees or managers see life through the eyes of someone of another color or culture. As the complexion of the work force in offices and factories changes, the idea is to get people to "value" diversity, rather than to ignore or resent it.

The training helps workers try to walk a mile in someone else's shoes, to imagine what it might be like to be the only black on the management team. Or to be working in a company where all the top executives share the same friends, schools and neighborhoods. Or to be the person who consistently gets passed over for promotion.

Mentors sign on for a year and are trained by Edmonson. It is up to the mentors to determine what kind of relationship they develop with students, but they must work with them to prepare for college. This means introducing students to various colleges, giving them career counseling and making sure all the paperwork that goes with applying for college is done. Special academic tutors work with students on specific subjects and in preparation for college-entrance tests.

About 20 Woodson students come to Fannie Mae each summer for an internship. The basic criteria for staying in the program and earning $500 a semester is pulling As and Bs in school.

Perhaps unintentionally, the mentor-scholarship program, with Edmonson at the blackboard, may drive home the diversity lessons better than any week-long training program or seminar for middle managers.

The lessons are learned the hard, unvarnished way, as in the morning when a mentor from Fannie Mae got a call from a former Woodson student who had gone on to college. The student was desperate, searching for help. Her boyfriend, perhaps jealous of her success, had paid a visit and beat her up. That same day, she found out that her mother was in a coma from a crack overdose. The mother later died.

Another mentor found she had not one, but two people as her responsibility: The student she had taken under her wing turned out to be a young mother.

"You are exposed to attitudes you are not familiar with. You can't make assumptions," said Rose McManus, assistant to the chairman at Fannie Mae and a mentor.

"We all had these stereotypical expectations about an inner-city school," said Harriet Ivey, the company's vice president of community relations and also a mentor.

More commonly, the bumps that mentors and students have along the way are cultural ones born of dissimilar upbringings, life experiences and expectations. Eventually, these are the sorts of differences that find their way into the workplace.

For instance, it takes a while for a white, middle-aged executive whose life is highly organized to figure out why some Woodson students don't respond to memos. Or why it takes a dozen times to get a phone call returned. Or why the students' and mentors' ideas of punctuality are radically different.

"The key cultural difference ... is the students have a laid-back approach and an amorphous approach to life," Edmonson said. "At Fannie Mae, everything is very driven and precise. It's an Afro-centric versus a Euro-centric approach. For example, the kids have a very soft view of time. For them, the party starts when everyone gets there."

Edmonson estimates that two-thirds of the 1,250 students at Woodson have personal lives that are at risk in some way. They live in one of the city's lowest income areas. Forty percent of the students come from families with incomes of $9,620 for a family of two to $24,440 for a family of eight. Not far from the school are two subsidized housing developments that have been the scene of street warfare with drug traffickers.

Among the students in the scholarship program, the range of family incomes is "tremendous," Edmonson said. Some are students from stable homes with supportive parents. But many are from "floating families," where the parents sometimes are there, sometimes not. Some are kids who basically raise themselves.

"What these kids lack are socialization experiences with people of other races. It's a 100 percent black school," said Edmonson. "Their world view is biracial instead of multiracial."

Edmonson knows where they are coming from because that's where he started his own life. Now he is a 40-year-old study in multiculturalism.

He was born blocks from Woodson, of working parents who are now comfortably middle class. His family eventually moved to a neighborhood near Catholic University. He went cross-town to school to be part of an experiment to integrate Sidwell Friends School in the mid-1960s.

"By the time I left Sidwell in 1967, I was, according to my peers, assimilated -- you act white, talk white, dress white," he said.

That's not the way Edmonson saw it: He simply became multicultural.

"There's a difference between affirmative action and affirmative diversity," he said. "It's not a loss of identity, but a gain."

His parents hoped he would go to Harvard University, but he chose a small school in northeastern Ohio -- Hiram College. There, he met his wife, Kathy, an Irish-Italian from Warren, Ohio.

He then spent five years studying clinical pastoral education at Duke University, working in the prison system, counseling youthful offenders, trying to reach adolescents in locked psychiatric wards.

He went back to Sidwell as a social studies teacher and was executive director of the Higher Achievement Program, which helps low-income children in Washington prepare for high school. Two years ago, he came to Fannie Mae.

Edmonson admits that to some of his black colleagues, he is an unsettling addition to the staff. They wonder why he was brought in from the outside to do a high-profile job. Others accuse him of pushing black kids to assimilate into a world where they will ultimately be forced to forsake their roots.

Some minorities dislike readings he gives to mentors about what it's like to be black in America, readings that discuss blacks' overexposure to drugs, violence, teenage pregnancy, urban poverty.

"There are blacks who would like him to put more of a facade on the bad things that happen in black communities," said Naomi Kinney, a mentor who is a Fannie Mae liquidation representative.

Other employees have different views. To many of them, he is an enigma. Is he another affirmative action program? Is he their conscience, making them face their most basic feelings and prejudices, however painful they may be? Some idolize him and the work he is doing.

Even with the students at Woodson, Edmonson stirs up crosscurrents of emotions.

"At first, the kids thought I was an uptown brother in a suit," he said.

Now, when he pulls up in the Woodson parking lot at 55th and Eads streets in his seven-year-old Mercedes with his leather briefcase, Vuarnet sunglasses and snappy navy blue double-breasted suit, many trust him and think his success is a good thing.

Students in the Fannie Mae program vie for Edmonson's attention when he drops in to check on how a new tutor is working out.

"He has a lot of great ideas about scuba diving," John Euill, a senior, tells Edmonson. Marguerite Smalls, another senior, brags to Edmonson that she got a 100 on a trigonometry test.

The effect on the Woodson kids is undisputed. Each year, more of them get a crack at scholarship money and college. Twenty-five of the first class of 71 went to college; this year, 37 of 132 were college-bound. But even without college, the students still come to understand the importance of having good communications skills and the ability to work with all kinds of people. Those who do well stand the chance of getting a job offer someday at Fannie Mae.

"If you can master the etiquette of a Fortune 500 company, you can adjust to any environment but still retain your sense of community and identity at Woodson," Edmonson said.

For the mentors, whose experiences have rippled throughout the company, the results are at once subtle and dramatic. There is more awareness of black culture. People who are not mentors ask what it's like to cross what they consider to be a cultural divide. Mentors learn about themselves.

There are experiences like the one Janice Daue, Fannie Mae manager of corporate public relations, had last January when she volunteered to help chaperon 45 students from Woodson on a campus tour at Virginia Polytechnic Institute and State University in Blacksburg, Va.

The group was walking around campus when a feeling came over her like a shiver. People -- white people -- were looking at them and whispering about them. "I thought, 'This is the way blacks must feel every day,' " Daue said.

For Edmonson, that observation is a lesson learned. "Here is the beginning of understanding," he said.