Fritz Haber's story is the story of the double edged sword of science. He won the Nobel prize in 1918 for his groundbreaking work in breaking the nitrogen cycle for Germany's WWI efforts, but it's been estimated that two out of every five people now living would not have been born if it weren't for artificial fertilizers created using his process. He also spent much of the war developing poison gases; first chlorine (after watching its first use, Haber's wife committed suicide) and later Zyklon B (the cyanide insecticide later used against his fellow Jews in concentration camps). He died alone and in poverty in Switzerland. But the lessons of his life haven't quite been forgotten.