Witold's Report, also known as Pilecki's Report, is an official report of over 100 pages (in its final version) written in 1943 by Witold Pilecki, a soldier in the Polish Army and a secret agent of the Polish resistance, who entered and escaped from the Auschwitz concentration camp. It was the first comprehensive record of a Holocaust death camp to be obtained by the Allies.
The report includes details about the gas chambers, "selektion", and the sterilization experiments. It states that there were three crematoria in Birkenau able to burn 8000 people daily. Raul Hilberg wrote that the Office of Strategic Services in London, which received the report, filed it away with a note that there was no indication as to its reliability.
Pilecki's Report preceded and supplemented the "" by Jerzy Tabeau (who escaped with Roman Cieliczko on 19 November 1943 and compiled the report between December 1943 and January 1944), the earliest of the three eyewitness reports known jointly as the which warned about the mass murder and other atrocities that were taking place inside the camp.
On November 9, 1939, after the Polish Army was defeated in the Invasion of Poland, the cavalryman Witold Pilecki together with his commander Major Jan Włodarkiewicz founded the Secret Polish Army (Tajna Armia Polska, TAP). In 1940, Pilecki presented to his superiors a plan to enter Germany's Auschwitz concentration camp, gather intelligence on the camp from the inside, and organize inmate resistance. At that time little was known about the Germans' running of the camp, as it was then an internment or large prison camp. His superiors approved the plan and provided him with a false identity card in the name of "Tomasz Serafiński". On September 19, 1940, he deliberately went out during a Warsaw street roundup (łapanka), and was caught by the Germans along with some 2,000 innocent civilians. After two days' detention in the Light Horse Guards Barracks, where prisoners suffered beatings with rubber batons, Pilecki was sent to Auschwitz and was assigned inmate number 4859.