This volume includes six essays, the firstdating from 1935 and the last from 1967, by one of the outstandingeconomists of our time. The economics presented in this volume ispolitical economy worthy of the name: a discipline which shows us thesocial relations, in particular the class and group conflicts, behindthe economic quantitative relations. Michal Kalecki, as Joan Robinsonhas pointed out, anticipated the Keynesian system, from a training inthe field of Marxist economics. The translation to English was executedby the author himself, just before his death in April 1970.