After the bitter civil war in 1936-39, Franco’s regime subjected the defeated republicans to severe repression and many thousands fled into exile (especially into France). Resistance in the form of guerrilla fighting and major strikes organized by clandestine groups flared up in 1946-47, but was decisively crushed. In the longer term, however, the Franco regime began to change, moving after 1957 from economic autarky and fascist Falangist ideal of an agricultural society towards incorporation into western capitaliost development. In 1962 Spain applied to join the EEC (the forerunner of the European Union), giving opposition intellectuals an opportunity to set out in the ‘Munich Manifesto’ the political reforms required to make Spain an acceptable member of the European Community.
From the 1960s there was both a reduction in poverty, as sectors of society benefited from economic growth and tourism, and some liberalization. Many prisoners had been released in a series of amnesties, and some discreet dissent was tolerated. Although the regime still harshly repressed any active form of dissent, worker and student resistance grew. There was a wave of strikes and student demonstrations in 1956, and 1962 saw the biggest strike since the Civil War, led by the miners of Asturias; students joined the protest. Throughout the 1960s, and with added momentum in the early1970s, workers engaged in wildcat strikes (all strikes were officially illegal and workers were controlled by the fascist-style syndicates). Alongside underground trade unions, workers’ committees bridging old ideological divides sprang up to organize the strikes and infiltrate the official syndicates. Student protest increased and intellectuals also engaged more openly in dissent. Apart from the Basque country, where ETA developed its long running campaign of guerrilla warfare, opposition groups relied primarily on unarmed tactics (although demonstrators quite often engaged in street battles, sometimes with the right-wing Falangists).
After Franco’s death in November 1975, Spain began its transition to democracy, holding free elections in 1977, which the previously underground opposition parties contested legally. A final threat to democratic stability was posed by the attempted military coup in February 1981, when Lieutenant Colonel Tejero led a group of Civil Guards in an attack on parliament when it was in session.. This attempt was, however, soon aborted by the refusal of the palace to back the coup and the willingness of the military high command to obey the king and suppress the plotters.
Most of the literature on the Franco regime is of course in Spanish, including the most comprehensive book on the early opposition: Heine, Hartmut , La oposición al franquismo: de 1939 a 1952 Critica, , 1983, pp. 502 . But there are some English language studies of Francoism which give weight to opposition, and a few studies specifically of resistance. Various websites have archival material from during the dictatorship – for example, http://libcom.org/history has reports from the Asturian miners’ strike by French Situationist Guy Debord.