An essay is an unofficial document on Wikibooks, written to express a particular opinion about the project. Essays that advocate a particular method of doing things may become an official policy or a guideline if they are accepted by the community at large. Essays can be used in a discussion to distill and solidify a particular viewpoint, so that people don't need to be constantly arguing the same points over and over again.
Essays, unless they are generally accepting as being important for the community, should be written in the User: namespace.
Essays that violate Wikibooks policies or guidelines may be deleted.