Now ninety, Bob Cousy, the Hall of Fame Boston Celtics captain who led the team to its first six championships on an unparalleled run, has much to look back on in contentment. But he has one last piece of unfinished business. The last pass he hopes to throw is to close the circle with his great partner on those Celtic teams, fellow Hall of Famer Bill Russell, now 84. These teammates were basketball's Ruth and Gehrig, and Cooz, as everyone calls him, was famously ahead of his time as an NBA player in terms of race and civil rights. But as the decades passed, Cousy blamed himself for not having done enough, for not having understood the depth of prejudice Russell faced as an African-American star in a city with a fraught history regarding race. Cousy wishes he had defended Russell publicly, and that he had told him privately that he had his back. He confided to Gary M. Pomerantz over the course of many interviews that at this late hour, he would like to make amends.