THE BESTSELLING book Roots, Alex Haley's historical reconstruction of how his family came from relative freedom in Africa to certain slavery in America, and then from slavery to relative freedom today, has spurred many black Americans to think about and search out their own roots.

A few years ago most blacks were either ashamed or afraid to tell the story of their struggle for survival against enormous odds.Their reticence derived in part from the frequent ugliness of their stories.

On these four pages are the true stories of eight Washingtonians who not only survived exploitation but went on to achieve prominence in a world dominated by whites.

Dr. LaSalle Doheny Leffall Jr., 46, has been a professor and chairman of the department of surgery at Howard University Hospital since 1970.

On his mother's side, Leffall can trace his roots back to his great-grandfather, Paul Moore, who was a slave in Virginia owned by a man named Paul Moore. As it happened, the white Paul Moore's daughter married a Dr. Jordan (pronounced Jerdan as in Hamilton Jordan), and soon afterwards Leffall's great-grandfather married Flora Jordan, a slave on the Jordan place who also happened to be the daughter of the white Dr. Jordan. The black Paul Moore changed his name to Paul Jordan9, apparently because the Jordans were a more important family.

About that time the white Jordans decided to move to Maysville, Alabama, a tiny town near Huntsville, because the doctor had heard that land opportunities were better there. The black Jordans moved with them.

In 1861, Paul and Flora Jordan produced Jeremiah Jordan, LaSalle Leffall's grandfather, who worked for the Jordans even after the war. Other members of the Jordan family sharecropped, but Jeremiah worked in the house. He also taught "the colored school" in the mornings, having been taught to read and write by the Jordan family.

When he was 32 years old he fell in love with "a dazzling beauty" of 16 named Carrie from Paint Rock, Alabama; they married and had seven children, one them LaSalle Leffall's mother. They managed to send her to Alabama Normal, then a two-year college, where she met LaSalle Leffall Sr., an agriculture teacher there. They got married in 1928 and moved to Quincy, Florida, for better teaching jobs. LaSalle Jr. was born there in 1930.

The family name is from the owner of a plantation in Louisiana - a Frenchman named LaSalle Leffall. The family, whose original name has been lost, were slaves in Georgia, but took on the Leffall name when they were sold to the Frenchman. The first black LaSalle Leffall was murdered by his Louisiana owner when it was discovered that the slave had been taught to read and write.

After the Civil War - when he was freed - Leffall's grandfather left Louisiana searching for wider opportunities. Somehow he became the owner of a 250-acre farm in east Texas. (The family speculates that he got ownership by squatter's rights, since he had no money). His son, LaSalle, left home when he was 15 years old and worked his way through high school and college in Prairie View, Texas, the only one of eleven children to go to college. After graduation he went on to Iowa State University, where he was awarded a degree in 1927. Then he was offered the teaching job at Alabama Normal.