“I remember degradation, starvation, and dead bodies lying on the street,” said Jan Karski. “My guide kept repeating: ‘Look at it, remember, remember.’ And I did remember.” Karski was a Catholic Pole. Born in 1914, his given name was Jan Kozielewski. He trained as a diplomat, but when the Nazis invaded his country in 1939, he fought as an officer in Poland’s 5th Regiment. Captured a number of times, Karski always escaped. He was an intrepid resistance fighter and an important courier who traveled between Poland, France, and Britain. Two times he was secreted into the Warsaw Ghetto so that he could report on what was happening there, hence the quote above. His heroism was touched with moral gravity. And yet leaders in the West, hearing his description of Holocaust atrocities, couldn’t grasp the magnitude. After the war, Karski moved to D.C. and became a professor of Eastern European affairs at Georgetown University. Decorated, honored, renowned, he died in 2000. Remember This: The Lesson of Jan Karski is a solo show written by Clark Young and Derek Goldman, starring the superb David Strathairn as Karski. First performed in 2019, it went to London in 2020 for the 75th Anniversary Commemoration of the Liberation of Auschwitz. The play, with Strathairn, is now at the Polonsky Shakespeare Center in Brooklyn, through October 9. —Laura Jacobs