Ludwik Witold Rajchman (1 November 1881 – 13 July 1965) was a Polish physician and bacteriologist. He is regarded as the founder of UNICEF, and served as its first chairman from 1946 to 1950. Family He was born to Aleksander Rajchman, the founder and first director of the Warsaw Philharmonic, and Melania Hirszfeld, a socialist and women's rights activist. He was from a family of Christianized Polish Jews. While his parents were agnostic, Ludwik was baptized at birth. He is the brother of Aleksander Rajchman, a prominent Polish mathematician and of Helena Radlinska, a Polish sociologist and he is the first cousin of Ludwik Hirszfeld, a Polish microbiologist. Ludwik Rajchman is the father of Jan A. Rajchman, a Polish computer scientist, inventor of magnetic-core memory. Biography Rajchman grew up in Warsaw in the difficult conditions of the Russian occupation. At an early age, he and his sister Helena became keenly aware of the social injustices in their "country" (Poland did not officially exist at the time) and were involved as teenagers in teaching young workers. As an adult, he joined the Polish socialist party (PPS) and was involved in the 1905 uprising and even arrested. After several months in prison he was exiled for a while to Kharkov. Ludwik Rajchman studied medicine at the Jagiellonian University in Kraków, where he met his future wife, Marja Bojanczyk who was also a medical student. He became fascinated by bacteriology as taught to him by Odo Bujwid who had worked with Louis Pasteur. Rajchman did his post-doctoral studies at the Pasteur Institute in Paris, then briefly returned to Kraków (he was banned from going to the Russian-occupied part of Poland), before being named to a prominent bacteriological laboratory in London. Rajchman and his wife and three children remained in London throughout the First World War, during which time Rajchman was kept busy also as a PPS activist lobbying for Polish independence after the war. The family returned to Warsaw in October 1918 and Rajchman (who was well acquainted with the Polish elite thanks to his family connections) persuaded the new Polish authorities to create an epidemiological center, subsequently renamed "Państwowy Zakład Higieny" (National Institute of Hygiene) which exists in Warsaw to this day as Poland's main public health institute. Rajchman was very active in the fight against several waves of a typhus epidemic which was devastating Eastern Europe and as such was noticed