Science fiction and fantasy have different characteristics, but they are often marketed together in bookstores and libraries. Science fiction builds on current scientific knowledge and theory or starts from the premise that current scientific theories will be proven wrong in the future. Fantasy, on the other hand, often creates other worlds that may bear little if any resemblance to our own; these worlds are populated with odd creatures and strange people who use magic, sorcery, talismans, and an assortment of other-worldly skills and talents. In both genres, the writer doesn't have to worry much about the reader's willing suspension of disbelief; the reader is out for escapism, and her disbelief is suspended as soon as she picks up the book.

Sci-Fi Elements

Science fiction can take a number of forms, from the futuristic vision of Star Trek to the alternate humanity of Animal Farm. Aliens, parallel universes, accidents or incidents that change history, new frontiers, postapocalyptic life, the dangers of technology — any one of these elements or a dozen others (and in virtually any combination) is a commonly occurring factor in science fiction. In most cases, the writer is expected to explain the technology, basing it either on known science or on a repudiation of known science. The main exception to this rule is the “space opera,” a futuristic version of the western, in which the battle between good and evil — with virtue emerging triumphant — takes precedence over the hardware.

So-called “hard” science fiction is based on real, present-day science and usually features one or more of the “hard” sciences like physics, chemistry, astronomy, and mathematics. A plot that can't survive the excision of the science element is called “hard” science fiction. Conversely, “soft” science fiction is based more on the social sciences, like sociology and psychology. “Soft” science fiction tales can often be transferred to any other setting without losing their basic integrity.

Fantasy Elements

Fantasy novels generally take place in mystical worlds with creatures like dragons and unicorns. A fantasy world may be earthlike, but it is usually far removed from the earth we know today; the exception is “modern” fantasy, where magic, sorcery, and other elements are fused in a contemporary setting. So-called “high” fantasy usually has a medieval setting and features strong class distinctions, often pitting staunch and true peasants against sly and greedy noblemen. Mythology and the Arthurian legends often provide the seed of the fantasy plot.

Like the action/adventure genre, fantasy usually involves a quest of some sort. The protagonist may set out to rescue a damsel in distress, to find a lost treasure, or to recover a magic amulet from an evildoer. Usually, the hero or heroine is young and naive, but possesses extraordinary courage and is helped in his or her quest by a wise and powerful mentor. Fantasy often takes on the flavor of an epic, spanning vast territories and introducing large casts of characters to the reader.

In fantasy fiction, morality is usually unambiguous. The characters are involved in a battle between good and evil, and evil nearly always appears to be stronger, smarter, faster, and more likely to win than good. To be able to resist the force of evil, the protagonist gets help from his allies, but in the end he must draw upon his own undiscovered resources to claim victory.