I'm currently reading The Rise and Fall of Communism by Archie Brown. Prof. Brown has clearly put a lot of research into the book, but his straightforward writing style, and lack of academic jargon, makes the work accessible to the average adult reader.
One of the more interesting things that Brown explores is how Communist regimes could last so long in so many different countries despite their many political and economic shortcomings. So long as the people believed their current hardship would lead to a better future, they were willing to put up with oppression. But over time, that utopianism became harder to sustain in the face of a harsh reality. The book quotes a joke from Khrushchev's time that perfectly captures the problem with Communism:
"A certain lecturer, speaking about the future communist society, concluded with the following remarks, 'The breaking day of communism is already visible, gleaming just over the horizon.' At this point an old peasant who had been sitting in the front row stood up and asked, 'Comrade Lecturer, what is a horizon?' The lecturer explained that it is a line where the earth and the sky seem to meet, having the unique characteristic that the more you move toward it, the more it moves away. The old peasant responded: 'Thank you, Comrade Lecturer. Now everything is quite clear.'"