It is a generally accepted standard that editors should attempt to follow, though it is best treated with common sense, and occasional exceptions may apply. Any substantive edit to this page should reflect consensus. When in doubt, discuss first on the talk page.
Hatnotes are short notes placed at the very top of an article or a section. As an example, see the notes in italics immediately preceding the boxes above. The name comes from their placement, as a hat is placed on top of one's head. The purpose of a hatnote is to help readers locate a different article if the one they are at is not the one they're looking for. Readers may have arrived at the article containing the hatnote because:
Link directly to other articles; do not pipe non-disambiguation links. Linking to redirects is typically not preferred, although of course exceptions can occur. Links to disambiguation pages should always end in "(disambiguation)", even when that version of the title is a redirect.
Mention other topics and articles only if there is a reasonable possibility of a reader arriving at the article either by mistake or with another topic in mind.
However, if a notable topic X is commonly referred to as "Foo", but the article "Foo" is not about X, there must be a hatnote linking to the article on X or linking to a disambiguation page that contains a link to the article on X.