Jan Karski, born Jan Romuald Kozielewski, was a Polish diplomat, soldier, and academic, known for his role as an eyewitness to the Holocaust. During World War II, he served as a courier for the Polish Underground State. His most important mission was to inform Allied leaders about the ongoing extermination of the Jews. After infiltrating the Warsaw Ghetto and a Nazi transit camp, he traveled to London and Washington to present his report, meeting, among others, British Foreign Secretary Anthony Eden and U.S. President Franklin D. Roosevelt. In 1944, he published the memoir *Story of a Secret State*, which described his experiences. After the war, he settled in the United States, teaching for decades at Georgetown University. For his heroism, he was named Righteous Among the Nations by Yad Vashem, received the Order of the White Eagle, Poland's highest honor, and the U.S. Presidential Medal of Freedom (posthumously).