It is a good question, and it seems like the original intent of Wikibooks was to restrict itself to some form of academia. Then again, what that is is open to interpretation: for example, the English courses at my university requires you to buy six novels and a short story anthology, as they are "textbooks" in the sense of required reading material. Some mathematics courses here, however, have a required textbook but is almost never used, so we can't really call it a textbook even though it's required material. So how a book is used in any academic context is not part of the definition of a textbook. If all else fails, let's look at Wikipedia's article on textbooks: A '''textbook''' is a [[manual]] of [[instruction]] or a standard [[book]] in any branch of [[study]]. Let's work off of that and find a good definition everyone can agree on. The problem is that any culinary academy's textbooks will talk more about the techniques of cooking rather than simply be a repository for recipes. Even my high school cooking textbook has absolutely zero recipes, as you were expected to come up with something on your own. In comparison, Cookbook in Wikibooks is nothing but a recipe repository, at least in the eyes of the greater community, even if there is material on techniques. When a lot of people think about jokebooks, they think of stuff that is marketed for children as some form of fiction, not reference material. I, for one, have not seen any jokebooks intended for adult audiences in the same vein (the large majority of them being comics and other satirical books, not like those Q and A ones for children). Still, comedy theory, IMO, is something that is learned and not taught. What do we consider a textbook? Is "DOS for Dummies" a textbook? Is "Teach Yourself SQL in 10 Minutes" a textbook? Most of us think of it as reference material, and very few places I know about actually use it as teaching material.