Short answers, pulled from the story.
Eurocommunism was a political trend among Western European communist parties in the 1970s and 1980s that rejected Soviet influence and argued for a distinctly Western European path to social transformation. It was especially prominent in Italy, Spain, and France, where the Italian Communist Party, the Communist Party of Spain, and the French Communist Party each engaged with the movement to varying degrees.
According to a ruling by the West German journal Deutschland Archiv in April 1977, the term was first used in the summer of 1975 by Croatian journalist Frane Barbieri, who had previously served as editor of the Belgrade news magazine NIN. The term's origin was subject to significant debate in the mid-1970s, with attribution also suggested for figures including Zbigniew Brzezinski and Arrigo Levi.
The Soviet crushing of the Prague Spring in 1968 is commonly considered the event that prompted Eurocommunism. It forced communist parties across the world to publicly align or break with Moscow. The Italian Communist Party and the Communist Party of Spain denounced the invasion, while the French Communist Party expressed disapproval, marking the first time in its history it had publicly criticised a Soviet action.
Santiago Carrillo, leader of the Communist Party of Spain, wrote Eurocomunismo y estado (Eurocommunism and the State), published in 1977. It is considered the defining book of the Eurocommunist movement. Carrillo also participated in drafting Spain's liberal democratic constitution as the country transitioned out of Francisco Franco's dictatorship.
Yes. In his memoirs, Mikhail Gorbachev cited Eurocommunism as a key influence on his ideas of glasnost and perestroika.
The Soviet Union's collapse put leftist parties across Europe on the defensive. Many Eurocommunist parties split, with right factions such as the Democrats of the Left moving toward social democracy while left factions like the Communist Refoundation Party sought to preserve communist positions. In 2017, the Communist Party of Spain formally returned to Marxism-Leninism.