Novotny ousted; Dubček appointed as Communist Party leader.
Action Programme introduced in April, known as 'Prague Spring.'
'Socialism with a human face' policy proposed by Dubček.
Reforms included: allowing minor parties in government, more democratic rights, equal Slovak rights.
Learned from Hungarian uprising, assured no plans to leave Warsaw Pact or Comecon.
Opposition, led by intellectuals, launched criticisms on radio and TV.
Summer saw emergence of radical ideas, including the allowance of a rival Social Democratic Party.