In his Capital, Marx throughout maintained the simplifying theoretical precondition that the value of labour is fixed and constant. However by this he mostly closed out discussing problems concerning class struggle and the organisational level of the working class from the analysis of capitalism in Capital. The connection, that increasing productivity results in proportionally higher profit only if the working class remains disorganised or its segmentation increases, receives little attention. Nevertheless, the capital immanently and necessarily aims not only increasing productivity but also deepening divisions among workers.

The new political thinking and practice, on which the idea and practice of the popular front was built, essentially opposed the general political thinking of its time. The Seventh World Congress of Comintern did not discuss ready-made thought-blocks and distilled ideas – it had to face the failure of the final-target oriented policy of communist parties in the political and social situation had developed by the 1930's. The antifascist popular front was both necessary political practice and a result of theoretical considerations.

The comprehensive study thoroughly analyses the history of the Spanish Civil War, circumstances of its outbreak and its political and social structure. The author gives special attention to military history considerations and connections to global politics.

As it is known, during the Spanish Civil War, the Republic received relevant state support only from the Soviet Union. The article reviews careers of some Soviet military advisers arrived to the Spanish front.

During Barcelona May Days, clashes broke out between troops of the popular-front government and radical revolutionary forces in May 1937. By analysing the events of the uprising and the following retaliation, the article values the chances of the popular front policy in a special historic constellation – during the revolutionary upheaval.