The various chapters can stand on their own, befitting short stories, but they relate a timeline of human interacton with Mars. As with the exploration of Earth by the European powers, these interactions are not truly to the benefit of either humans or Martians. The first few meetings lead to the death of the human explorers, but in a tip of the hat to H. G. Wells' War of the Worlds, the Martians are nearlly wiped out by an illness from Earth.
I found it very interesting that The Martian Chronicles had a chapter (April 2005: Usher II) that was essentially devoted to reflecting Poe's works. In that chapter, the protagonist character took out his frustration against the gross censorship of books that became the central point of Bradbury's next novel, Fahrenheit 451. Poe is recorded as being one of his early influences, and he fills this particular chapter with many of the nightmares of Poe's most famous stories. He slowly replaces the censors with robots, meanwhile killing each of them using Poe's murderous ideas. In the final scene, as per Poe' The Cask of Amontillado, the investigator is manacled and walled up behind brickwork, because he had never read any literature, all having been destroyed.