One of Cortazar's most celebrated tales, "Axolotl," is told by a man who becomes an axolotl, a type of salamander, after spending countless hours watching them in an aquarium. Even in his new form, he continues to observe his past human self and hopes that this human will write a story about a man transforming into an axolotl. Many critics see the axolotl's final comment as the core theme of Cortazar's short fiction—suggesting that through art, one can become another and express the voices of all beings, ensuring that no one feels the fear of isolation and confinement.

"Axolotl" was released during a time when Cortazar had moved from Argentina to Paris, France. The story is set in Paris and seems to unfold during the period it was written. Critic Terry J. Peavler has noted that Jean-Paul Sartre's existentialist philosophy, a major intellectual movement of the time, influenced "Axolotl." Existentialism, which began in France, inspired many writers in the 1950s, including Irish playwright Samuel Beckett and French authors Albert Camus and Jean Genet. Peavler compares "Axolotl" to Sartre's book Being and Nothingness, which was published in the same year.

Sartre argued that people create their own identities through their choices and actions. While individuals should not see themselves as a fixed set of traits or categories, they also should not consider themselves as mere nothingness. At the end of the story, the axolotl hopes the narrator will "write all this about axolotls" to find the existential balance between being (the rational mind celebrated in most Western philosophies) and nothingness (the unconscious mind, represented by the axolotl's primitive nature). The story suggests that achieving this balance requires experiencing both extremes, as the narrator has, before such self-awareness becomes attainable.