Military Organization Union

Związek Organizacji Wojskowej (Polish: [ˈzvjɔ̃zɛk ɔrɡaɲiˈzat͡sji vɔj'skɔvɛj], Military Organization Union), abbreviated ZOW, was an underground resistance organization formed by Witold Pilecki at Auschwitz concentration camp in 1940.

In 1940, Witold Pilecki, a member of the Polish resistance organisation Tajna Armia Polska (Secret Polish Army, TAP, later known as Armia Krajowa or Home Army), presented a plan to enter Germany's Auschwitz concentration camp, gather intelligence from the inside, and organize inmate resistance. His superiors approved this plan and provided him with a false identity card in the name of "Tomasz Serafiński". On 19 September 1940, he deliberately went out during a łapanka in Warsaw, and was caught by the Germans along with other civilians and sent to Auschwitz. He was the only known person ever to volunteer to be imprisoned in Auschwitz.

In the camp Pilecki was known as Tomasz Serafiński (Prison Number 4859) and began the work of organising the Związek Organizacji Wojskowej (ZOW). ZOW would become the Auschwitz branch of Armia Krajowa and its aims were to improve inmate morale, provide news from outside, distribute extra food and clothing, and set up intelligence networks.

ZOW was organized in a cell network of "Fives", whereby all five agents knew nothing about their comrades. The first "Five" was formed out of Pilecki's TAP members, various captured soldiers of the Polish army. It included: Dr. Władysław Dering - number 1723, Lieutenant-Colonel Władysław Surmacki - number 2795, Jerzy Hlebowicz - the false name of Captain Jerzy de Virion - number 3507, Eugeniusz Obojski - number 194 and Roman Zagner - number unknown. This group was nicknamed the "High Five" of ZOW. Its commander was Lieutenant-Colonel Władysław Surmacki.

By 1941 ZOW had grown substantially with "High Five" creating numerous sub-groups. Despite being an arm of the Polish resistance, membership was not limited to Poles, though Jewish members had a much lower life expectancy since the Germans prioritized exterminating Jews over Polish prisoners. Notable members of ZOW included the famous Polish sculptor Xawery Dunikowski and ski champion Bronisław Czech.

ZOW members worked in the camp's SS administration office (Mrs. Rachwalowa, Capt. Rodziewicz, Mr. Olszowka, Mr. Jakubski, Mr. Miciukiewicz), the [magazines]^{[definition needed]} (Mr. Czardybun), and the Sonderkommando, which burned human corpses (Mr. Szloma Dragon and Mr. Henryk Mendelbaum). The organisation had its own system of enforcing order (with a secret criminal court), as well as supply lines to the outside. Thanks to civilians living nearby, the organisation regularly received medical supplies. Inmates even constructed a radio receiver and hid it in the camp hospital.

Many smaller and non-Polish underground organisations at Auschwitz eventually merged with ZOW. In the autumn of 1941, Colonel Jan Karcz was transferred to the newly created Birkenau death camp, where he proceeded to organise more ZOW structures. By the spring of 1942, the organization had over 1,000 members, including women and people of other nationalities, at most sub-camps.

Meanwhile, the Gestapo redoubled its efforts to ferret out ZOW members, and from late 1942 succeeded in killing many of them.