PRAGUE The enormous mass movement that has essentially overthrown Czechoslovak communism rose up with amazing speed. By the last week in November millions of people had participated in demonstrations across the country. Yet as recently as October 28--Czechoslovakia’s independence day--dissidents could bring only 10,000 people into the streets. These brave souls had scarcely unfurled their pro-democracy banners before truncheon-wielding police were chasing them through Prague's winding Gothic lanes. Three weeks later throngs of hundreds of thousands of people were routine in Wenceslas Square.