There was a time when David Blackwell, the first black member of  the National Academy of Sciences, was shunned by his colleagues because of his race, denied the right to attend lectures and do research at Princeton University and blocked from a post at the University of California, Berkeley. The mathematician and statistician eventually became Berkeley's first black professor, and this week, nearly two years after his death at age 91, the institution is joining with Howard University and the American Statistical Association to celebrate his legacy and contributions with a conference in his memory.