Sam Kean told much of this story in his excellent book, The Disappearing Spoon (primarily in chapter 5 - and I know that this link has to be flouting copyright law entirely).
There are details here that I didn't know, but the story of Haber should be more well known. He was one of the most brilliant scientific minds of our modern world, but he was - in a charitable description - more concerned with the science than with the ethics of his science. In a less charitable description, Haber was a bastard.
He found a way to synthesize ammonia from nitrogen in the atmosphere, a discovery that lead to modern fertilizers which allowed us to become a world of nearly 8 billion people and prove the Malthusians wrong.
That discovery is one of the most important in shaping our world.
He absolutely deserved his Nobel prize.
He also found a way to turn that fertilizer into explosives for the Germans in World War I.
And he developed a way to produce chlorine gas which was then used on the battlefield, choking soldiers in merciless, painful ways.
...for which Haber was promoted in the German army.
His wife killed herself - possibly because of his involvement in chemical weapons - and Haber headed onward to the front to supervise more use of chlorine gas.
Oh, and Haber's institute developed Zyklon B, the gas used in the gas chambers on the German concentration camps.
(Great animation at 9:30, by the way)
