Why did the Socialist System Collapse in Central and Eastern European Countries?

In the book the author discusses the reasons for the collapse of the socialist system in Poland, Czechoslovakia and Hungary. He analyses the roles of economic and political factors and of the USSR. He concludes that the lack of legitimacy of the communist regime, the disintegration of the Communist Party and its ideology were at least as important reasons as increasing lag behind the West in technology and the declining standard of living.