Karski was a brilliant young diplomat when war broke out in 1939 with Hitler's invasion of Poland. Taken prisoner by the Soviet Red Army, which had simultaneously invaded from the East, Karski narrowly escaped the subsequent Katyn Forest Massacre. He became a member of the Polish Underground, the most significant resistance movement in occupied Europe, acting as a liaison and courier between the Underground and the Polish government-in-exile. He was twice smuggled into the Warsaw Ghetto, and entered the Nazi's Izbica transit camp disguised as a guard, witnessing first-hand the horrors of the Holocaust.
Poland -- History -- Occupation, 1939-1945.
World War, 1939-1945 -- Personal narratives, Polish.
World War, 1939-1945 -- Poland.