The novel follows a group of Earth explorers on a journey to Venus, where they encounter a highly advanced civilization of human-like beings who descended from Atlantis and have embraced a spiritual and ascetic way of life.

Zaziemskie światy's blend of interplanetary travel, Atlantis myths, and critiques of industrial society aligns it with earlier European speculative fiction in the tradition of Jules Verne.

[2][5][6] The inhabitants of Venus, ruled by the "Great Magician", consider themselves more advanced than Earthlings, having abandoned a civilization or culture focused on excessive material needs, and living "in harmony with nature" (they are, among other things, advocates of vegetarianism).

The meaning of the pseudo-philosophical musings spread throughout the work boils down to a primitive condemnation of material civilization and the glorification of passive contemplation, which is supposed to represent the ideal of human aspirations at the highest level of spiritual development".

[5] Andrzej Niewiadowski [pl] and Smuszkiewicz assess that the experiences of World War II were "a severe blow to the positivist worldview" of the aged writer and led him to an "ideological turn" and "revolutionary change", abandoning the vision of progress brought about by scientific and technical civilization in favor of an apologia for the spiritual transformation of man.

[14] Kamila Budrowska [pl] cites the opinions of censoring reviewers, who attributed to the novel "an inappropriate ideological basis" and "completely obscure social ideas" with "modest popular-scientific values".

[2] Additionally, censors criticized the author's fascination with the United States: "The book, written in an atmosphere of admiration for America, millionaires, and margraves, seems harmful and should not be published" and "the implication to the reader of the extraordinarily favorable conditions for the development of science and technology in a capitalist system, which has a particular significance in the current period of the march towards socialism".