The Uprising was the largest military effort by an occupied country during WWII. It began August 1 1944 and was crushed totally 63 days later.
It had been planned as part of Operation Tempest, the Polish plan to rise against the Germans as soon as they were to retreat from Poland--a plan begun in Sept. 1942. The plan was to take governmental control and re-establish a Polish army immediately in order to re-establish the rest of Polish civil and military organization. The Poles wanted the Allies to see that there was a Polish government and civil authorities. Poles felt highly pressured to do this quickly.
The immediate army to be formed was to be based on the pre-war Polish army, and the names of the divisions were to be used for the Home Army that was to form. The Uprising was to have 3 stages, first to take place nearest the Red Army, then to proceed into areas of less threat. Since diplomacy between the Polish government and the Soviet had been broken in 1943 (After Germans notified the Poles of a 1940 Soviet massacre of all [22 000] captive Polish officers) by Soviet Secret Police Stalin broke refused to answer and broke off relations), the Poles feared the Soviets would not liberate them as friends, and whose propaganda would brand them impotent or collaborationist.
In considering the importance of the Uprising, the Poles bore in mind that the Ukrainian Army had, between 1943 and 1944, in other regions of occupied Poland, ethnically cleansed those areas by official policy (to purge all non-Ukrainians from the future Ukrainian state of all male Poles ages 16-60 [though more women and children were killed than men]).
Prior to the Warsaw Uprisings, there had been other instances of Polish armed uprisings against the Germans, coordinating with the Red Army, but each time after victory the Red Army imprisoned them or forced them to convert to the Red Army or being sent to Soviet Labor Camps.
Besides the common enemy of Germany, the Poles and Russians were antagonistic, the Poles wanting to reinstate their government and pursue a democratic, Western-allied future and the Soviets wanted to install a communist government and make a satellite of Poland.
The occupying Germans had been preparing Warsaw to meet the uprising.
On the eve of the Uprising, the Red Army was approaching Warsaw, and from Soviet-controlled radio stations were calling for Poles to rise in arms"
"The Polish Army of Polish Patriots... calls on the thousands of brothers thirsting to fight, to smash the foe before he can recover from his defeat... Every Polish homestead must become a stronghold in the struggle against the invaders... Not a moment is to be lost."
"Fight the Germans! No doubt Warsaw already hears the guns of the battle which is soon to bring her liberation. [...] The Polish Army now entering Polish territory, trained in the Soviet Union, is now joined to the People's Army to form the Corps of the Polish Armed Forces, the armed arm of our nation in its struggle for independence. Its ranks will be joined tomorrow by the sons of Warsaw. They will all together, with the Allied Army pursue the enemy westwards, wipe out the Hitlerite vermin from Polish land and strike a mortal blow at the beast of Prussian Imperialism."

The Uprising was put off for days, and, although the Poles had prepared for a series of coordinated night attacks which would last a few days until the Red Army reinforced them, the Uprising was ordered in daylight and the Soviets waiting out the conflict from the other side of the river. In the important, establishing first days of the conflict, the separate Polish forces had varying degrees of successes, but managed to hold most of Warsaw, although not Castle Square, the police district, or the airport, and the Polish forces failed to link up.
The Germans retreated until they met up with reinforcements and a new General, after which they pursued an attack, and killing all civilians door-to-door behind their lines. The lines became more stable, and the Germans eventually won the conflict, forcing cornered Poles to flee. Those who did not escape were either shot or sent to concentration camps. The Poles signed the capitulation order Oct 2.
Germany sent the entire Warsaw population to a transit camp. Of 350 000 - 550 000 civilians, 90 000 were sent to labor camps, 60 000 to death and concentration camps, and the rest were shipped to various locations and released. Germany ordered the utter destruction of the remainder of the city.
The Red army and the Allies during the Uprising. After the Red Army fought its way to the Vistula River, the Kremlin ordered the army to halt and it deliberately (or, according some some historians, because they were simply unable to help) did not aid the Poles, and instead stayed put watching the German-Polish conflict zone, providing only sporadic artillery and air support. The Allies had provided assistance to the Poles by airlifts of supplies, but Stalin had not permitted them to use the airbases in Poland (requiring them to use England's and Italy's), calling the Poles as "a handful of criminals."
When the Soviets took Warsaw in January they were able to say they "liberated" Warsaw.
Stalin did not let the Polish government in exile return, instead installing his choice of Soviet-subservient government.
(Excepts.)
Cooper testified as a "friendly" witness:
ROBERT E. STRIPLING, CHIEF INVESTIGATOR: When and where were you born, Cooper?
GARY COOPER: I was born in Helena, Montana, in 1901.
STRIPLING: What is your present occupation?
COOPER: An actor.
STRIPLING: Mr. Cooper, you are here in response to a subpoena which was served upon you on September 26, are you not?
COOPER: Yes, I am.
STRIPLING: Chairman, the interrogation of Mr. Cooper will be done by Mr. Smith.
CHAIRMAN: We will have more order, please.
H.A. SMITH: Mr. Cooper, how long have you been an actor?
COOPER: I have been an actor since 1925.
SMITH: And how long have you been in Hollywood?
COOPER: Since 1924.
SMITH: I believe you made many pictures, some of which pictures are "Unconquered," "Pride of the Yankees," "Saratoga Trunk," "Mr. Deeds Goes to Town," and you are presently making "Good Sam," is that correct?
COOPER: Yes.
SMITH: Are you a member of the Screen Actors Guild?
COOPER: Yes, I have been a member since the guild was organized.
SMITH: During the time that you have been in Hollywood, have you ever observed any communistic influence in Hollywood or in the motion picture industry?
COOPER: I believe I have noticed some.
SMITH: What do you believe the principle medium is that they use (in) Hollywood or the industry to inject propaganda?
COOPER: Well, I believe it is done through word of mouth ...
CHAIRMAN: Will you speak louder, please, Mr. Cooper?
COOPER: I believe it is done through word of mouth and through the medium of pamphleting -- and writers, I suppose.
SMITH: By "word of mouth," what do you mean, Mr. Cooper?
COOPER: Well, I mean sort of social gatherings.
SMITH: That has been your observation?
COOPER: That has been my only observation, yes.
SMITH: Can you tell us some of the statements that you may have heard at these gatherings that you believe are communistic?
COOPER: Well, I have heard quite a few, I think, from time to time over the years. Well, I have heard tossed around such statements as, "Don't you think the Constitution of the United States is about a 150 years out of date?" and -- oh, I don't know -- I have heard people mention that, well, "Perhaps this would be a more efficient government without a Congress" -- which statements I think are very un-American.
SMITH: Have you ever observed any communistic information in any scripts?
COOPER: Well, I have turned down quite a few scripts because I thought they were tinged with communistic ideas.
SMITH: Can you name any of those scripts?
COOPER: No, I can't recall any of those scripts to mind.
CHAIRMAN: Just a minute. Mr. Cooper, you haven't got that bad a memory.
COOPER: I beg your pardon, sir?
CHAIRMAN: I say, you haven't got that bad a memory, have you? You must be able to remember some of those scripts you turned down because you thought they were communist scripts.
COOPER: Well, I can't actually give you a title to any of them, no.
CHAIRMAN: Will you think it over, then, and supply the committee with a list of those scripts?
COOPER: I don't think I could, because most of the scripts I read at night, and if they don't look good to me, I don't finish them, or if I do finish them I send them back as soon as possible to their author.
MCDOWELL: That is the custom of most actors, most stars, Mr. Cooper?
COOPER: Yes, I believe so, yes, sir. As to the material, which is more important than the name of the script, I did turn back one script because the leading character in the play was a man whose life's ambition was to organize an army in the United States, an army of soldiers who would never fight to defend their country. I don't remember any more details of the play, but that was enough of a basic idea for me to send it back quickly to its author.
SMITH: Mr. Cooper, have you ever had any personal experience where you feel the Communist Party may have attempted to use you?
COOPER: They haven't attempted to use me, I don't think, because, apparently they know that I am not very sympathetic to communism. Several years ago, when communism was more of a social chit-chatter in parties for offices, and so on when communism didn't have the implications that it has now, discussion of communism was more open and I remember hearing statements from some folks to the effect that the communistic system had a great many features that were desirable. It offered the actors and artists -- in other words, the creative people -- a special place in government where we would be somewhat immune from the ordinary leveling of income. And as I remember, some actor's name was mentioned to me who had a house in Moscow which was very large -- he had three cars, and stuff, with his house being quite a bit larger than my house in Beverly Hills at the time -- and it looked to me like a pretty phony come-on to us in the picture business. From that time on, I could never take any of this pinko mouthing very seriously, because I didn't feel it was on the level.
SMITH: Mr. Chairman, we have several official documents that we have obtained through the State Department, which I believe clearly shows that the Communist Party attempts to use actors individually throughout the world to further their cause. With your permission, I would like to show one of those documents to Mr. Cooper and have him read it to the committee. This document from which Mr. Cooper is going to read was distributed in pamphlets in Italy during May of 1947. ...
COOPER: Shall I read it?
SMITH: ... by the Communist Party. Yes, sir, go ahead.
COOPER: Gary Cooper, who took part in the fights for the independence of Spain, held a speech before a crowd of 90,000 in Philadelphia on the occasion of the consecration of the banner of the Philadelphia Communist Federation. Between other things, he said: "In our days it is the greatest honor to be a communist. I wish the whole world to understand what we communists really are. There could be nobody then who might say that we are enemies of mankind and peace. Those who want to discuss communist ideas should first get to know them. ...
SMITH: Were you ever in Philadelphia, Mr. Cooper?
COOPER: No, sir, I was never in Philadelphia.
SMITH: Do you have any comment to make regarding this letter?
COOPER: Well, a 90,000 audience is a little tough to disregard, but it is not true.
CHAIRMAN: I want to help you along, Mr. Cooper. ...
COOPER: No part of it is true, sir.
CHAIRMAN: I happen to know it is just a plain, ordinary, ruthless lie. We know that for a fact. So you don't have to worry any more about that.
MCDOWELL: And also, Mr. Cooper, in order to get it into the record, don't you think there wouldn't be 90,000 people in Philadelphia who were communists?
COOPER: Well, I believe it was Mr. Smith here that said you would have a hard time getting 90,000 people out in Philadelphia for anything. I don't know about that. ...
STRIPLING: Mr. Cooper, witnesses who have preceded you from Hollywood have said that they consider members of the Communist Party to be agents of a foreign government. Do you consider the members of the Communist Party to be that?
COOPER: I am not in nearly as good a position to know as some of the witnesses that have been ahead of me, because I am not a very active member in our guild. They, therefore, know much more about the politics and the workings of what communists there are in the guild than I. From the general, overall things that you hear in Hollywood, I would assume that there is such a close parallel. ...