Bruno de Finetti (June 13, 1906 - July 20, 1985) was an Italian probabilist and statistician, noted for the "operational subjective" conception of probability. The classic exposition of his distinctive theory is the 1937 "La prévision: ses lois logiques, ses sources subjectives," Annales de l'Institut Henri Poincaré, 7, 1-68, which discussed probability founded on the coherence of betting odds and the consequences of exchangeability.

Work
De Finetti was born in Innsbruck, Austria and studied mathematics at Milan University. After graduation, he did not pursue an academic career but worked as an actuary and a statistician. He published extensively (17 papers in 1930 alone, according to Lindley) and acquired an international reputation in the small world of probability mathematicians. He won a chair in Financial Mathematics at Trieste University (1939). In 1954 he moved to the University of Rome, first to another chair in Financial Mathematics and then, from 1961 to 1976, one in the Calculus of Probabilities. De Finetti developed his ideas on subjective probability in the 1920s independently of Frank P. Ramsey. He only became known in the Anglo-American statistical world in the 1950s when L. J. Savage, who had independently adopted subjectivism, drew him into it; another great champion was Dennis Lindley. De Finetti died in Rome.

de Finetti in English
The following books have a chapter on de Finetti and references to further literature.

D. V. Lindley, "Bruno de Finetti, 1906-1985 (Obituary)" Journal of the Royal Statistical Society, Series A, 149, p. 252 (1986).
Jan von Plato, Creating Modern Probability : Its Mathematics, Physics, and Philosophy in Historical Perspective, Cambridge: Cambridge University Press, 1994
Donald Gillies, Philosophical Theories of Probability, London: Routledge, 2000.