For the downvoters: Fritz Haber co-invented (with Carl Bosch) the Haber-Bosch ammonia synthesis process, without which most people on Earth would not be alive.
He is also credited as the father of chemical warfare, and directly ran and oversaw development of chlorine and other poison gas weapons for Germany in WWI.
His wife, Clara Immerwahr, committed suicide, using her husband's service revolver, and was found mortally wounded though not yet dead by her 12 year old son An act thought by many to have been a protest to her husband's work.
Parent comment is quite accurate.