There are many speculative fiction publications and methods of publication. These include novels, short stories and other short works, poetry, film, television, and artwork, and more recently has begun to include works published entirely online.
In keeping with its relation to Astounding Science Fiction, the style and approach of the stories in Unknown was a hybrid between those of fantasy and science fiction. The premises of many of the stories were caused by unexpected, and often humorous, situations in which a traditional fantasy creature or concept is introduced into an otherwise ordinary world. For example, in de Camp’s "Nothing in the Rules", the manager of a swimming team tries to win a race by including a mermaid on the team.
Other stories take the opposite trope of applying a scientific logic in a traditional fantasy setting; the Harold Shea series is based upon the premise that traditional fantasy worlds, such as those in Norse mythology, are based upon the rules of mathematical logic.
Unknown also included some science fiction which used the themes of traditional fantasy. For example, Darker than You Think uses the premise that werewolves exist, but that they are not supernatural, and explains the traditional beliefs about them without using fantasy.