I think sci-fi and fantasy writers make a fatal mistake that restricts the number of readers they can reach: they assume too much specific knowledge of anyone picking up their book. They expect that whoever opens up their tome is going to know exactly which knights sat around the Round Table, or the name of the little pixies that gambol through a Hawaiian rain forest, or what a day in the life of a neutron is like.
They write to the devoted sci-fi, fantasy reader who has plowed through every book previously written on the subject and has memorized all of Edith Hamilton’s histories of Greek and Roman mythology.
Anyone who casually picks up these writers’ books, will be befuddled by references to little-known minutiae of fact or fantasy featured as major plot points. These poor, befuddled people come from a group known as Mainstream Readers. This is a very big group of people. These people read classics, and mysteries, and action-adventures, and thrillers, and all of those books you frequently see at the front of the bookstore, where they put bestsellers.
If I talk to any of my friends who are mainstream readers and mention the words science fiction, they noticeably cringe. Many of these people are attracted to the world of sci-fi and fantasy. They have been impressed with things like Star Wars and Avatar and Harry Potter in the movie theater and have ventured so far as to crack open a new genre book only to find that it’s about as understandable as the instruction manual for computer software. (Particularly web software.)
Ask the authors of these books, and they will proudly proclaim that they’re not writing to the general public; no, they’re writing to those cognoscenti who reside in a thing they refer to as a Niche Market.
Definition: a small group of people.
However, if you look at the most recent smash success, Harry Potter, you’ll see what happens when all of the elements come together. Because the books are tailored for a young adult audience, they’re aimed at someone who has no prior knowledge of the genre. Therefore, things are explained. The reader is brought along with Harry as he learns new experiences. S/he doesn’t have to know about mandrakes, just follow along as Harry is taught about them. This motivates a great number (millions and millions) of mainstream readers came rushing in, along with the young adults, buying these books.
Mainstream readers are just as captivated by the imaginary worlds found in sci-fi and fantasy as are those devoted fans. They just need what amounts to a few extra sentences, at most, to explain what’s going on.