"A Princess of Mars is a science fantasy novel by American writer Edgar Rice Burroughs, the first of his Barsoom series. Full of swordplay and daring feats, the novel is considered a classic example of 20th-century pulp fiction. It is also a instance of the planetary romance, a subgenre of science fantasy that became highly popular in the decades following its publication. The story is set on Mars, imagined as a dying planet with a harsh desert environment. This vision of Mars was based on the work of the astronomer Percival Lowell, whose ideas were widely popularized in the late 19th and early 20th centuries.