Gajo Petrović was born in Karlovac on 12 March 1927. At the outset of World War 1, in 1941, he was in high school where he was already participating in a resistance movement. He soon became a member of the SKOJ (Socialist Youth Organization) and later of the Communist Party. Following his studies in the USSR, Petrović enrolled at the Faculty of Philosophy in Zagreb and in 1949 he wrote his first critical review of an article by Boris Ziherl in the daily Borba. The review received much publicity because Ziherl was, at the time, an unquestionable figure of authority inthe party’s Central Committee. Therefore, a move like this, by a 21 yearold student, seemed exceptionally brave.

Petrović experienced his first disappointment in early 1949, when the authorities imprisoned his good friend and several more philosophy students for criticising the Information Bureau. Petrović was charged as their intellectual leader, as they (party authorities) wanted to remove him from the university party organisation and ruin his reputation among students. Petrović was expelled from the Communist Party and was only returned to the university after many pleas were made to that effect.

Petrović graduated in February of 1950, and during the same year, he was appointed assistant at the Faculty of Philosophy. In the spring of 1955, he submitted his doctoral dissertation entitled Philosophical Views of G.F. Plekhanov, which he had defended before a dissertation committee in January of 1956. During those years Petrović published book reviews and his thoughts on contemporary philosophical issues in different Yugoslav journals. He had already started to study Heidegger and his interest in this philosopher did not leave him until the end of his life.

In the beginning of the 1960’s, he met Erich Fromm, who supported the publishing of his book Philosophy and Marxism in America. Starting in 1969, Petrović worked as tenured professor at the Department of Philosophy, where he taught ontology, epistemology and logic. As a visiting professor, Petrović gave lectures at many world’s universities. He is the co-founder of the Croatian Philosophical Society, Yugoslav Association for Philosophy and the Korčula Summer School. He was also vice-president of the Ernst-Bloch-Gesellschaft philosophical society.

Petrović was one of the founders and editor-in-chief of internationally renowned periodical Praxis that gathered a group of philosophers as its writers. Philosophy of Praxis, i.e. philosophy of practice, whose representatives, based on early works of Karl Marx, sharply criticized the Soviet type of Marxism and so became very influential in the former Yugoslavia in the 1960’s. The group advocated focusing on the creative potential of individuals and the problem of alienation. Petrović became the target of party criticism again in 1968 when he expressed his critical views and support for student demonstrations and for students’ gathering at the Zagreb Student Centre.

In 1986 four volumes of Petrović’s Selected Works were published, of which the third, titled Prolegomena za kritiku Heideggera (Prolegomena for criticism of Heidegger) was pronounced the most successful book of the year in that scientific field. Petrović was a great critic of nationalism and war. He died on 13 June 1993 in Zagreb.