Karl Landsteiner (1868-1943), was an Austrian biologist and physician. In 1900 he was the first to distinguish the main blood groups. He developed the modern system of classification of blood groups from his identification of the presence of agglutinins in the blood. In 1937, with Alexander S. Wiener, he identified the Rhesus factor, enabling physicians to transfuse blood without endangering the patient's life. In 1909 with Constantin Levaditi and Erwin Popper, he discovered the polio virus. In 1930 he received the Nobel Prize in Physiology or Medicine. He was awarded a Lasker Award in 1946 posthumously and is recognized as the father of transfusion medicine.