Karski’s real name was Jan Kozielewski.
He was born in 1914 in the city of Łódź into a middle-class family.
His promising diplomatic career was cut short by the outbreak of war.
After the defeat of the Polish army in October 1939, he fled to the Russian-occupied eastern part of Poland, where he was interned.
He was later deported deep into the Soviet Union and would likely have been executed – like most Polish officers – had he not concealed his rank and managed to join a group of ethnic German Poles being repatriated to western Poland.
After joining the anti-Nazi resistance, Karski undertook several courier missions, carrying dispatches from the Polish underground to the Polish Government-in-Exile in London.
During one such mission in July 1940, he was arrested by the Gestapo in Slovakia, tortured, and transported to a hospital in Nowy Sącz, from which he was rescued by the Polish resistance.
He soon resumed active service in the Information and Propaganda Bureau of the Home Army’s High Command.
In the summer of 1942, he was assigned another secret mission to London.
In preparation for this mission, and in order to gather first-hand evidence about the plight of Polish Jews, he was twice smuggled into the Warsaw Ghetto by Jewish underground leaders.
Having witnessed the horrors there, Karski became convinced that informing the world about the genocide of European Jews was the most important part of his mission.
He met several Allied leaders, including Britain’s Foreign Secretary Anthony Eden and US President Franklin D. Roosevelt, but failed to secure meaningful support for the Jews of Poland.
Many of those he spoke to believed he was exaggerating. Felix Frankfurter, the first Jewish justice on the US Supreme Court, told Karski bluntly: "I am unable to believe you."
After the war, Karski settled in the United States and became a professor at Georgetown University in Washington, DC.
His book Story of a Secret State, subtitled My Report to the World, was first published in the United States in 1944 and sold over 360,000 copies there by the end of the war.
Karski received numerous honors, including the Order of the White Eagle (Poland’s highest state distinction), the US Presidential Medal of Freedom, the Righteous Among the Nations medal from the Yad Vashem Institute in Jerusalem, and honorary citizenship of Israel.
Karski remained a tireless advocate for Holocaust remembrance until the end of his life.
He died on July 13, 2000, at the age of 86.
(mk/ał)