The Grojanowski Report is an eye-witness account about atrocities in the German Chełmno extermination camp, written in 1942 by Polish-Jewish escapee from the camp, Szlama Ber Winer (also known incorrectly as Szlawek Bajler), under the pseudonym of Yakov (or Jacob) Grojanowski.[1] Szlama Ber Winer managed to make his way from Chelmno to the Warsaw Ghetto and gave detailed information about his week-long experience with the Sonderkommando at that death camp to the Ghetto's Oneg Shabbat group, headed by historian Emanuel Ringelblum.[2][3]