Armia Ludowa (People's Army), or AL, was formed by the KRN (Krajowa Rada Narodowa - National Council of the Country) on 1 January of 1944, as a continuation of the Gwardia Ludowa (People's Guard), or GL. Its purpose was to unite all the left-wing Polish anti-Nazi resistance organizations into a common united front. Later on 21 July of 1944, it was merged with the Polish Military in U.S.S.R. to form the Ludowe Wojsko Polskie (Polish People's Military).

AL was a conspiratorial popular military organization established by, and subordinated to, the KRN. Its aim was to wage a military struggle alongside the U.S.S.R. and all the anti-fascist forces against the Hitlerite occupiers, in order to bring about a free Poland with a popular-democratic system.

AL had around 60 000 members, of which 12 000 were full-time field partisans and approximately 50 000 were part-time fighters. Of this number only about 10 000 AL troops came from the disbanded GL, with the majority coming from other left-wing resistance organizations that joined the AL, or, to a lesser degree, from "raw" growth. Besides having its members coming from the GL, they also came from the following: the entire Organization "Swit", all the combat units of the ZWM (Zwiazek Walki Mlodych - Union of the Youths' Fight), most of the ML RPPS (Milicja Ludowa Robotniczej Partii Polskich Socjalistow - People's Militia of the Polish Socialists' Labour Party), portion of the BCh (Bataliony Chlopskie - Peasant Battalions), and some units from the GL-WRN (Gwardia Ludowa-Wolnosc,Rownosc,Niepodleglosc - People's Guard-Freedom,Equality,Independence), KB (Korpus Bezpieczenstwa - Security Corps)^*, PAL (Polska Armia Ludowa - Polish People's Army)^*, and the SOB (Socjalistyczna Organizacja Bojowa - Socialist Combat Organization). All the units of the Polish Partisan Headquarters present on the occupied territory were also formally subordinated to the AL. In addition to these some units and individuals came from the AK (Armia Krajowa - Army of the Land), and two units and some individuals from the NSZ (those who did not agree with that organization's policies).

AL made a very significant contribution to the Polish Liberation War during WWII, in spite of being a target of attacks and murders of the fratricidal collaborators from the NSZ, and (in some cases) of right-wing extremists from the AK, and of having endured an additional ideological hostility from the top echelons of the AK leadership; facts that are unfortunetly nowdays very much overlooked and/or mis-represented. In spite of these difficulties, AL actively and frequently co-operated with other resistance organizations, including such major ones as the AK and BCh, as well as with the regular Soviet and Polish armies.

The armed effort of the AL in 1944 alone (the organization existed until late January of 1945), and according to incomplete data, amounted to about 1 100 various combat actions, including 620 actions directed against the occupier's transportation and communications lines, 340 engagements against the units of the Hitlerite Wehrmacht, SS, and police, as well as nine (9) larger partisan battles. In addition to these, the AL also made a significant contribution in the fields of political, social, and informational work, besides engaging in appropriating and counter-plundering actions, counter-intelligence and intelligence-gathering, freeing of hostages and/or prisoners, diversion and sabotage, dis-arming/arms-gathering actions, clandestine production of weapons, equipment, and materials, and etc.

* - As part of the PSZ (Polaczone Sily Zbrojne - Unified Armed Forces) of the AL-PAL-KB formed during the Warsaw Uprising, which recognized the KRN and the legitimate Polish government in Lublin.