Be sure to read it through the section called The Auschwitz Campaign: 945 days:
At Auschwitz, while working in various kommandos and surviving pneumonia, Pilecki organized an underground Union of Military Organizations (Związek Organizacji Wojskowych, ZOW). ZOW’s tasks were to improve inmates’ morale, provide them news from outside, distribute extra food and clothing to members, set up intelligence networks, and train detachments to take over the camp in the event of a relief attack by the Home Army, arms airdrops, or an airborne landing by the Polish 1st Independent Parachute Brigade, based in Britain…
…By 1943, however, he realized that no such plans existed. Meanwhile the Gestapo redoubled its efforts to ferret out ZOW members. Pilecki decided to break out of the camp, with the hope of personally convincing Home Army leaders that a rescue attempt was a valid option. When he was assigned to a night shift at a camp bakery outside the fence, he and two comrades overpowered a guard, cut the phone line and escaped on the night of April 26–April 27, 1943, taking along documents stolen from the Germans. In the event of capture, they were prepared to swallow cyanide to prevent the Germans learning the extent of their knowledge. After several days, with the help of local civilians, they made good their escape from the area and contacted Home Army units. Pilecki submitted another detailed report on conditions at Auschwitz.
(Thanks Markus. Wonderful link.)