Orlando Fals Borda

Orlando Fals Borda, who has died aged 83, was an internationally respected sociologist of Colombia and Latin America and distinguished political figure active on the left. His two-volume work, La Violencia en Colombia (1962), Compiled with Eduardo Umaña and Father Germán Guzmán, detailed the terrible period of peasant slaughter that lasted for a decade after the assassination of the Liberal leader, Jorge Eliécer Gaitán, in 1948. Soon recognised as a masterpiece, it introduced the complexities of Colombia's peasant politics to a wider world.

Fals Borda came to believe that it was the duty of a sociologist not just to examine the social reality of the country, but to try to remedy the grave injustices that research uncovered. A close collaborator, with whom he set up the first sociology faculty in Latin America at the National University of Bogotá in 1959, was Father Camilo Torres Restrepo, a charismatic priest who eventually joined the guerrillas of the National Liberation Army (ELN) and was killed in 1966. Fals Borda, equally committed to social and political change, chose a more peaceful road.

Born in Barranquilla, northern Colombia, the son of presbyterian parents, Fals Borda completed his education in the US. There he studied with Nelson Lowry at the University of Minnesota, and later with T Lynn Smith at the University of Florida. Equipped with a doctorate in sociology, he re-established himself in Bogotá, determined to introduce the social sciences into Colombia's conservative curriculum. He had acquired an encyclopedic knowledge of the Colombian countryside, and worked in the ministry of agriculture from 1959 to 1961, but he was not a natural bureaucrat and had little enthusiasm for Colombia's string of governments that ignored the peasant population, and preserved the rights of landowners. He soon found himself a niche among Colombia's leftwing intellectuals and activists, helping to found Alternativa, a famous radical magazine in the 1970s, together with the writer Gabriel García Márquez and the journalist Enrique Santos Calderón.

In his academic role, Fals Borda developed a methodology known as participatory action research, combining research and theory with political participation. This became popular in several Latin American universities and intrigued his many admirers in Europe and the US. For years he was denied a US visa, his contacts with peasant movements regarded as subversive, but he eventually returned with honour in April 1995 to attend a conference of southern sociologists in Atlanta. There he delivered a speech in which he outlined four of his own guidelines for sociology researchers: "Do not monopolise your knowledge nor impose arrogantly your techniques, but respect and combine your skills with the knowledge of the researched or grassroots communities, taking them as full partners and co-researchers. Do not trust elitist versions of history and science which respond to dominant interests, but be receptive to counter-narratives and try to recapture them. Do not depend solely on your culture to interpret facts, but recover local values, traits, beliefs, and arts for action by and with the research organisations. Do not impose your own ponderous scientific style for communicating results, but diffuse and share what you have learned together with the people, in a manner that is wholly understandable and even literary and pleasant, for science should not be necessarily a mystery nor a monopoly of experts and intellectuals."

In January 1979, Fals Borda fell foul of the security statute enacted during the regime of President Julio César Turbay Ayala. Together with his wife, María Cristina Salazar, he was arrested and held incommunicado for three weeks, falsely accused of involvement with the M-19 guerrilla group. He was freed without charge, but his wife was not released until the following year. The M-19 guerrillas later came down from the mountains and formed a political movement, the Alianza Democrática M-19, and Fals Borda became one of their elected members in the constituent assembly of 1991. Later he became honorary president of the Polo Democrático Alternativo, which supported Carlos Gaviria as presidential candidate at the 2006 elections.

Fals Borda wrote innumerable books and articles, publishing in 2003 after the death of María Cristina, an autobiographical memoir, Antes la Crisis del País, in which he recalled his friendship with Camilo Torres and reiterated his beliefs in the tenets of liberation theology.

· Orlando Fals Borda, sociologist and political activist, born July 11 1925; died August 12 2008