Otto Hahn, OBE, ForMemRS (8 March 1879 – 28 July 1968) was a German chemist and pioneer in the fields of radioactivity and radiochemistry. He was exclusively awarded the Nobel Prize in Chemistry in 1944 for the discovery and the radiochemical proof of nuclear fission. He is referred to as the father of nuclear chemistry.
Hahn was an opponent of national socialism and Jewish persecution by the Nazi Party. Albert Einstein wrote that Hahn was "one of the very few who stood upright and did the best he could in these years of evil". After World War II, Hahn became a passionate campaigner against the use of nuclear energy as a weapon. He served as the last President of the Kaiser Wilhelm Society (KWG) in 1946 and as the founding President of the Max Planck Society (MPG) from 1948 to 1960. Considered by many to be a model for scholarly excellence and personal integrity, he became one of the most influential and respected citizens of the new Federal Republic of Germany.
Hahn was the youngest son of Heinrich Hahn (1845–1922), a prosperous glazier and entrepreneur ("Glasbau Hahn"), and Charlotte Hahn, née Giese (1845–1905). Together with his brothers Karl, Heiner and Julius, Otto was raised in a sheltered environment. At the age of 15, he began to take a special interest in chemistry, and carried out simple experiments in the laundry room of the family home. His father wanted Otto to study architecture, as he had built or acquired several residential and business properties, but Otto persuaded him that his ambition was to become an industrial chemist.