Feltrinelli is perhaps most famous for his decision to translate and publish Boris Pasternak's novel Doctor Zhivago in the West after the manuscript was smuggled out of the Soviet Union in the late 1950s.

At the instigation of Giangiacomo's monarchist mother, Giannalisa, Italian dictator Benito Mussolini had him created Marchese di Gargnano at the age of 12 by King Vittorio Emmanuele III.

During the Second World War, the family left the Villa Feltrinelli[5] in Gargnano, north of Salò, to be occupied by Mussolini, and moved to Monte Argentario.

[6] The young Feltrinelli first took an interest in the living conditions of the poor and working class during discussions with the staff who ran his family's estate.

According to some interpretations, Sindona was pushed to buy out Feltrinelli by the Vatican Bank, a minority shareholder embarrassed by cohabitation with a communist partner.

[6] The Library later became an Institute; later still the Giangiacomo Feltrinelli Foundation, possessing some 200,000 rare and modern books, extensive collections of newspapers and periodicals (both historical and current), and over a million primary source materials.

[citation needed] In late 1956, an Italian journalist showed Feltrinelli the manuscript of Doctor Zhivago by the Russian writer Boris Pasternak.

[13] His son Carlo's biography of Feltrinelli[6] records a correspondence between him and Pasternak as they successfully resisted clumsy attempts by the Soviet regime to halt publication of the novel.

[16] The communist leadership in Moscow, which had not wanted the book published, criticised Feltrinelli, who in turn decided not to renew his PCI membership in 1957.

He also took the risk of publishing and distributing novels banned under Italian obscenity laws, such as Henry Miller's Tropic of Cancer.

Feltrinelli published the writings of figures such as Castro, Che and Ho Chi Minh, and a series of pamphlets on the unfolding insurgencies and wars in Southeast Asia and the Middle East.

In 1970, fearing a right-wing coup d'etat, he founded the militant Gruppi di Azione Partigiana (Partisan Action Groups, or GAP).

[6] On 15 March 1972, Feltrinelli was found dead at the foot of an electricity pylon at Segrate, near Milan, apparently killed by an explosive device he and other GAP members were planting the day before.

[29] They also admitted that Feltrinelli was not obsessed with a neo-fascist coup, because he wanted to establish in Italy the armed struggle and was one of the first to have had contacts with the German Red Army Faction:[29] finally they affirmed that the relationships between GAP and RB were characterized by the maximum correctness, without competitive spirit.