A person who reads, whether they love to read or simply are able to read, is a reader. If you're a fan of a particular author, you're also one of her readers.
If you write children's books, you need to keep your readers in mind as you tackle difficult topics or use complicated language. Your readers are all the kids who will be reading the words you write. Another type of reader checks manuscripts for typos, or decides if they're good enough to be published as a book or in a magazine. Students who are learning to read sometimes use a book called a reader for practicing reading skills.