Stanley G. Weinbaum's "A Martian Odyssey," Frederic Brown's "Arena," and Frank Belknap Long's "Invasion" portray variety of aliens. Alien is a kind of character common to many science fiction works. We have talked about how other worlds or aliens or machines can be regarded metaphors of society and times. In well developed essay, study theme of alien encounters in stories mentioned above. You may want to distinguish the ways in which authors see importance of "the alien," or think about "the alien" as typical character in science fiction and compare it with characters in mainstream fiction. Conclusion must bring together all ideas about aliens you have developed in paper and explain possible significance of "alien" as element of science fiction.