Spanish communist born in Zaragoza, in the Aragon region of north Spain, into a petty-bourgeois republican family. Around 1930 his family moved to Madrid and shortly after he began studying architecture. In the early 1930s he joined the Communist Youth, eventually becoming an important leader in it, and in 1936 took part in it's unification with the Socialist Youth to form the United Socialist Youth.
In the first few months of the Civil War, he fought on the Guadarrama front, later becoming involved in propaganda and organizing work, as well as being an important assistant to the junta for the defense of Madrid. In 1937 he was elected to the Spanish Communist Party's Central Committee. Spent the final year of the war reorganizing the defense in the republican center-south region. The same day that Madrid fell, he was able to escape to Oran, Algeria, where he was temporarily put in a concentration camp before making his way to the Soviet Union. From there he was sent to Paris to direct the press of the United Socialist Youth. Fleeing the Nazi occupiers after the beginning of WWII he spent the war in exile between Mexico, Cuba, Chile and Argentina.
After the war he returned to France where he helped organizing documents, arms, and propaganda to be sent into Spain, and in 1946 was selected to join the party's Politburo. In 1947 he was sent to Moscow to represent the party and experienced first-hand the postwar period of intense Stalinist paranoia and repression. In 1955 he was sent to Paris again to direct the party's ideological and educational work. After working hard to organize the "National Strike" of 1959, including an underground presence in Madrid, and seeing it's spectacular failure, Claudín began to question the tactics imposed on them by the Soviet Union and the party's tendency to disdain instead of encourage open debate of ideas and plans.
Claudín and others continued to critique the party's past behavior and advocate for drastic changes, including greater internal democracy in the party and independence from Soviet diktats and petty interference. This led to Claudín being expelled from the party in 1964, after which Claudín began dedicating himself to translation and writing. He returned to Madrid in 1975, the year Franco died. As Spain slowly returned to liberal democracy, Claudín became an advocate of "Eurocommunism" or radical social democracy. Claudín remained active on the left in Spain and a committed progressive until his death.
The Communist Movement (1970)
Important two-part book that deals with the Comintern and Cominform from a leftist anti-Stalinist perspective. Especially important due to the lack of writing from this perspective on the functioning and experience of the Comintern, much less the Cominform.
Part One: The Crisis of the Communist International: 389 pages. A detailed analysis of the Comintern from it's beginning to its dissolution, a sacrifice on the altar of Stalin's alliance with the western powers. Deals with the concrete problems that stunted it's growth: i.e. lack of revolutions in Europe between the world wars and it's theoretical shortcomings. Also discussed in length is the "ultra-centralism" of the decision making inside the Comintern: i.e. it carrying out blindly whatever the Soviet party decided with little to no influence of any other party. Also deals extensively with the massive failures of the Comintern, some well known such as the collapse of the German Communist Party, the continual damage caused to the Chinese Revolution, the various anti-fascist fronts in Spain and France among other places, and others not such as the shameful arming of Ataturk (by Lenin) as he massacred communists and Armenians and in general it's poor performance in colonized countries.
Part Two: The Zenith of Stalinism: 436 pages. Details the important late-WWII and post-war period with special focus on the communist resistance movements in Europe, the Cominform, and the final, post-war period of Stalinist repression. Claudín deals with the Soviet-centered policies forced on the two biggest European communist parties in France and Italy, which forced them to forgo any revolution in their countries, even though they were armed, popular, the largest parties in their country, and facing an extremely weakened bourgeoisie. Claudín then goes on to discuss the communist parties which refused these Soviet-centered policies and launched revolutions in Greece, Yugoslavia, and China and how these parties were systematically betrayed by the Soviet Union. An important analysis of the Cominform period about which little has been written, especially from an independent Marxist perspective.