What is the difference between a book challenge and a book ban?
According to the American Library Association, a challenge "is an attempt to remove or restrict materials, based upon the objections of a person or group. A banning is the removal of those materials. Challenges do not simply involve a person expressing a point of view; rather, they are an attempt to remove material from the curriculum or library, thereby restricting the access of others."
In other words, a challenge can result in a ban. Not every challenge results in a ban. And, sometimes, books are not completely removed from a particular library or school. Instead, books or other materials are moved from easily accessible shelves to a restricted section, are restricted to a specific age group, or have other requirements that impede free access to the book. This is still considered censorship, but different people may or may not consider this to be a "ban."