> In the U.S., are there any books that are really banned, e.g. unable to be sold, purchased, possessed? How is that a useful definition? The term is vague, s

> In the U.S., are there any books that are really banned, e.g. unable to be sold, purchased, possessed? How is that a useful definition? The term is vague, so don’t pick a definition that doesn’t contribute any useful understanding.