Character Analysis
Chamberlain was the Prime Minister of Great Britain (the United Kingdom) from 1937 to 1940. He's gone down in history as a symbol of appeasement toward Adolf Hitler's Germany in the period before WWII.
Shirer describes the Prime Minister as having a fatal "inability to comprehend the mind of Adolf Hitler" (3.9.17), and throughout the book he repeatedly criticizes the conciliatory stance that Chamberlain took toward Germany's Nazi Fuehrer.
Shirer's most intense scorn is reserved for Chamberlain's participation in the negotiations that led to the Munich Agreement in September 1938.
The truth was that Runciman had been forced down the throat of the Czech government by Chamberlain. But there was an underlying and bigger falsehood. Everyone, including Chamberlain, knew that Runciman's mission to "mediate" between the Czech government and the Sudeten leaders was impossible and absurd. […] [T]he Czechs knew perfectly well that Runciman had been sent by Chamberlain to pave the way for the handing over of the Sudetenland to Hitler. It was a shabby diplomatic trick. (3.12.102)
Chamberlain was hailed as a hero when he first returned to England after the signing of the Munich Agreement. Shirer's comments on Chamberlain throughout TRFTR make it pretty clear that—from Shirer's point of view—if Winston Churchill had been in the driver's seat in 1938, history would have taken a very different turn.
After Hitler had proven to the world that he lied about all his intentions and was aiming to subjugate most of Europe, Chamberlain saw the consequences of his policy of appeasement. When France was attacked and Britain entered the war, Chamberlain said:
This is a sad day for all of us, and to none is it sadder than to me. Everything that I have worked for, everything that I have believed in during my public service, has crashed into ruins. […] I trust I may live to see the day when Hitlerism has been destroyed and a liberated Europe has been re-established. (3.17.154)
He didn't.
After he died in 1940, Winston Churchill remembered him in a generous way:
…It fell to Neville Chamberlain in one of the supreme crises of the world to be contradicted by events, to be disappointed in his hopes, and to be deceived and cheated by a wicked man. But what were these hopes in which he was disappointed? What were these wishes in which he was frustrated? What was that faith that was abused? They were surely among the most noble and benevolent instincts of the human heart—the love of peace, the toil for peace, the strife for peace, the pursuit of peace, even at great peril and certainly in utter disdain of popularity or clamor. (3.17.156)
That's one way to look at it. But history didn't remember Chamberlain as kindly as Churchill did.