Gabriel Deville (8 March 1854 – 28 February 1940) was a French socialist theoretician, politician and diplomat. He was a follower of the Guesdist movement in the 1880s, and did much to raise awareness of Karl Marx's theories of the weaknesses of capitalism through his books and articles. Later, without abandoning his beliefs, he became more pragmatic and was twice a deputy in the National Assembly. After leaving office he accepted various diplomatic positions. Early years Gabriel Deville was born on 8 March 1854 in Tarbes, Hautes-Pyrénées. His family had a strong republican tradition. His grandfather was Jean-Marie-Joseph Deville(fr), Representative of the People from 1848 to 1851 during the French Second Republic. His uncle was Amédée Deville, vice-president of the Anatomical Society of Paris, who was proscribed after the coup d'état of 2 December 1851. Gabriel Deville attended secondary school in Tarbes, then studied in the faculties of law in Toulouse and Paris, where he obtained his license as a lawyer. Deville joined a Marxist section of the International Workingmen's Association in Toulouse as a 17-year-old student. Deville studied the works of Karl Marx, including the translation of Le Capital by Joseph Roy. Deville moved to Paris to complete his law degree in 1872, and joined the Latin Quarter radicals. He became one of the leaders of the discussions. Guesdist theoretician Talking of his early years Deville wrote, "In 1877 when I was one of those who began to propagate the collectivist and Marxist theory by the newspaper, I scarcely knew the rudiments ... We learned socialism at the same time that we informed our readers, and it is incontestable that we sometimes made mistakes." Deville's pamphlet Blanqui libre (1878) portrayed Louis Auguste Blanqui, now an old man, as a benign leader who had suffered from oppression. The pamphlet was vague about Blanqui's revolutionary principles. In the spring of 1879 Deville tried to give national publicity to the campaign to elect the imprisoned Blanqui as deputy for Bordeaux. He was the key figure in this Guesdist effort, which was seen as a form of national plebiscite on amnesty for the leaders of the Paris Commune. Throughout the 1880s Deville supported Jules Guesde's French Workers' Party (POF: Parti Ouvrier Francais). He contributed to Guesde's newspaper L'Egalité. Deville began to gain a reputation as a socialist theoretician. He wrote various works on socialism including Cours d'économie sociale – L'évaluation du capital (1884),