Edison's Conquest of Mars attempt at fiction, the book was published serially in the "New York Journal". Serviss went on to write other science fiction stories, arguably making him the first American to write science fiction professionally. An early example of what would later be called space opera, "Edison's Conquest of Mars" was also a particularly literal "Edisonade". The book contains some notable "firsts" in science fiction: alien abductions, spacesuits (called "air-tight suits": see Spacesuits in fiction), aliens building the Pyramids, space battles, oxygen pills, asteroid mining and disintegrator rays. The book is set following the abortive Martian attack depicted in "Fighters from Mars",
The Gods of Mars to Earth in pre-technological eras, particularly with the inclusion of kingdoms, empires or religious societies. Spacecraft may appear, but are not central to the story (something which makes these tales distinct from Space Opera, where spaceships are usually a key focus of the narrative). There were some Planetary Romances prior to the publication of the Barsoom novels, but "A Princess of Mars" and "The Gods of Mars" and other novels in the Barsoom series were the most influential on the numerous similar stories that were published subsequently. Burroughs's vision of Mars was loosely inspired by astronomical speculation of the time,