[7][8] In the wake of Being and Nothingness, Sartre became concerned with reconciling his concept of freedom with concrete social subjects and was strongly influenced in this regard by his friend and associate Maurice Merleau-Ponty, whose writings in the late 1940s and early 1950s, including Sense and Non-Sense, were pioneering a path towards a synthesis of existentialism and Marxism.

[10] More generally, Critique of Dialectical Reason was written following the rejection of Communism by leftist French intellectuals sympathetic to Marxism, a process that not only ended Sartre's friendship with Merleau-Ponty but with Albert Camus as well.

In it, Sartre puts forward a revision of existentialism, and an interpretation of Marxism as a contemporary philosophy par excellence, one that can be criticized only from a reactionary pre-Marxist standpoint.

[3] From the time the Critique of Dialectical Reason was published in 1960, there has been much discussion about where it stands in relation to Sartre's earlier, seminal work, Being and Nothingness.

[4] Sartre's analysis of "groups-in-fusion" (people brought together by a common cause) resonated with the events of the May–June 1968 uprising in France and allowed him to sideline for a while the competing influence of Louis Althusser's structuralist interpretation of Marxism.

[12] Situating the Critique of Dialectical Reason in the context of May–June 1968, the psychoanalyst Didier Anzieu stated that "Sartre first described in his book the passive and anonymous forms of individual alienation--this is what he calls the 'practico-inert'--and then he showed how a group introduces negation into history and shapes itself (instead of being shaped), invents itself by breaking with this passive and anonymous society that an American sociologist called 'the lonely crowd.'

[16] Leszek Kołakowski argues that the Critique of Dialectical Reason represents an abandonment of Sartre's original existentialism and that it absurdly depicts Marxism as "invincible".

Kołakowski nevertheless considers the book an interesting attempt to find room for creativity and spontaneity within Marxism, noting that Sartre rejects the dialectic of nature and historical determinism while preserving the social significance of human behavior.

In his view, Sartre gives such a generalized account of revolutionary organization that he ignores the real difficulties of groups engaging in common action without infringing the freedom of their individual members.