Short answers, pulled from the story.
The Critique of Dialectical Reason, published in 1960, is Sartre's attempt to synthesize existentialism with Marxism. Sartre argues that human beings are neither absolutely free nor slaves to circumstance, and that scarcity shapes social life in ways that diminish humanity. He contends that Communism, by abolishing shortages, would restore individual freedom.
Scholars have disagreed on this since 1960. George Kline saw the Critique as a repudiation of Sartre's existentialism, while Marjorie Grene argued it could be translated into the categories of Being and Nothingness. Fredric Jameson concluded that reading the Critique permanently changes how one reads Being and Nothingness.
The first volume, "Theory of Practical Ensembles," was translated into English by Alan Sheridan-Smith and published in 1976. A corrected translation appeared in 1991. The second volume, "The Intelligibility of History," was translated by Quintin Hoare and published in English in 1991.
Sartre is quoted as having called it the principal of his two philosophical works for which he wished to be remembered, ranking it above Being and Nothingness as the work he most wanted to be associated with.
Sartre's concept of "groups-in-fusion" resonated with the May-June 1968 student uprising in France. The psychoanalyst Didier Anzieu described the uprising as "the inroad of 'Sartrean' freedom, not that of the isolated individual but the creative freedom of groups." The concept also helped Sartre sideline the competing influence of Louis Althusser's structuralist Marxism during that period.
Leszek Kolakowski argued Sartre abandoned his original existentialism and never explained how Communism could restore freedom in practice. He also charged Sartre with introducing superfluous neologisms without genuinely advancing Marxist thought. Roger Scruton described the book as a rejection of the rules of intellectual enquiry, while Sidney Hook saw it as a justification for Soviet human rights abuses.