Short answers, pulled from the story.
The Munich Agreement was a pact signed at about 1:30 am on the 30th of September 1938 by Germany, the United Kingdom, France, and Italy. It transferred the Sudetenland, a border region of Czechoslovakia inhabited by roughly three million ethnic Germans, to Nazi Germany.
Czechoslovakia was deliberately excluded from the Munich conference negotiations, though its representatives were present in the city. Britain and France, seeking to avoid war with Germany, struck the deal without Czechoslovak participation, then informed Prague it must accept the terms or fight Nazi Germany alone.
Czechoslovakia lost 70 percent of its iron and steel industry, 70 percent of its electrical power, and 3.5 million citizens to Germany. The ceded borderland also contained its main defensive fortifications, leaving the remainder of the country militarily exposed. Poland and Hungary subsequently annexed additional territories.
Chamberlain delivered his famous "peace for our time" speech outside 10 Downing Street on the 30th of September 1938, reading from a joint declaration he and Hitler had signed. He described the settlement as the prelude to a larger peace for all of Europe.
Churchill denounced the agreement in the House of Commons on the 5th of October 1938, calling it "a total and unmitigated defeat" and warning that Czechoslovakia would be engulfed in the Nazi regime within years or months. He described it as "the first sip, the first foretaste of a bitter cup" that would be offered year by year.
The Soviet Union, which had mutual assistance treaties with both France and Czechoslovakia, felt betrayed by the agreement. Stalin concluded that the Western powers had colluded with Hitler and might do the same to the Soviet Union. This belief led to a reorientation toward rapprochement with Germany and ultimately contributed to the signing of the Molotov-Ribbentrop Pact in 1939.