Roy WilkinsHis grandfather was a slave, and his father tended a brick kiln. He worked at turns as a redcap, a dishwasher, a Pullman-car waiter and a cleanup man in a St. Paul slaughterhouse. But since 1931, when Roy Wilkins joined the staff of the National Association for the Advancement of Colored People, his name has been synonymous with the nation's oldest and largest civil-rights organization. His tenure, from 1955 to 1977, as the NAACP's chief executive embraced the era of greatest progress for black Americans. Though he lacked the magnetism of Martin Luther King Jr. or the fire of Stokely Carmichael, he quietly made an enduring contribution to the cause of equal rights, embodying the will of the majority of black citizens to work within the system. When he died last week in New York City of kidney failure,just after llis 80th birthday, he left behind a landscape of broken barriers and a lifetime in the fight for integration-against the recalcitrant South and, later, against the forces of separatism within his own race.