In the book Under a Cruel Star, did communism suceed in creating a classless society in Czechoslovakia?

In the book, Under a Cruel Star: A Life in Prague 1941-1968, we learn that the Communists were not successful in creating a classless society. According to the author's commentary, the fundamental concept is that tyranny, in whatever form, is evil and destructive. The book ends with a political commentary detailing the Prague Spring of 1968, and the immediate results of that transient upheaval.