Bulgarian-born socialist revolutionary, a Bolshevik politician and Soviet diplomat and statesman; he was also noted as a journalist, physician, and essayist. Rakovsky's political career took him throughout the Balkans and into France and Imperial Russia; for part of his life, he was also a Romanian citizen.

A lifelong collaborator of Leon Trotsky, he was a prominent activist of the Second International, involved in politics with the Bulgarian Workers' Social Democratic Party, Romanian Social Democratic Party, and the Russian Social Democratic Labour Party.

He came to oppose Joseph Stalin and rallied with the Left Opposition, being marginalized inside the government and sent as Soviet ambassador to London and Paris, where he was involved in renegotiating financial settlements. He was ultimately recalled from France in autumn 1927, after signing his name to a controversial Trotskyist platform which endorsed world revolution.

Credited with having developed the Trotskyist critique of Stalinism as "bureaucratic centrism", Rakovsky was subject to internal exile. Submitting to Stalin's leadership in 1934 and being briefly reinstated, he was nonetheless implicated in the Trial of the Twenty One (part of the Moscow Trials), imprisoned, and executed by the NKVD during World War II.