When Margie Eugene-Richard won the Goldman Prize last year, it was a stunning public recognition of decades of struggle. Richard -- the first African-American to win the award, which some refer to as environmentalism's Nobel Prize -- had waged a 30-year campaign against Shell Chemicals with fellow residents of Diamond, La. Like the proverbial David, the African-American, working-class neighborhood took on a Goliath -- and won. Diamond by Steve Lerner, MIT Press, 344 pgs., 2005. But the fight against Shell was not just the singular achievement of an individual activist, as Richard would be the first to admit. It was …