Through one reader's comments, I just recently realized that there's a "language" of fantasy novels. This reader is an accomplished editor with many published books to her credit; mostly non-fiction. She apparently doesn't read much fantasy, because she doesn't understand the language of it. I thought I would share a few things to educate those of you who don't read fantasy, or have tried to read it and don't "get" it.
What makes a book a fantasy is usually one of three things: 1) it's set in a place that doesn't exist; 2) it involves animals or peoples that don't exist; 3) it involves use of magic or other supernatural powers. Other than that, it is simply a novel.
Many, probably most, fantasies, are set in either a medieval or renaissance time period. This gives the writer a set of customs, language, dress, and technology that is well documented that they can describe easily because there are paintings and resource materials available. Technologically emergent civilizations are based on the Victorian time period. Other tales are based on either Chinese, East Indian, and Islamic societies of the same time periods. All of these settings are somewhat familiar, because they are based on human history. It's very easy to make up a geography and political map, decide what time period and culture your group of people live in, and then go forward with your story. Any ordinary novel that is set in an entirely fictional place, especially if it includes a map inside the front cover, or has an established dating system not used on earth, is a fantasy.
There are certain well-established fictional people and animals you can include in your story, and with a little research, you can understand the mutually agreed-upon "rules" governing them: elves, dwarves, goblins of many sorts, leprechauns, fairies of several sorts, unicorns, gryphons, phoenixes, and so forth. Any ordinary book that includes one or more of these groups is a fantasy.
Any book involving the use of magic, witchcraft, mind-reading, telekinesis, or any other mental or physical power, including power learned through study is a fantasy.