Copyright (c) 2012-2016 Hyperion Entertainment and contributors.
AmigaGuide is a hypertext system widely used in AmigaOS for documentation. You'll find AmigaGuide files included with most Amiga software: they usually contain information such as Installation Instructions, Software Requirements, Features, Keyboard Shortcuts, Help and Advice, and legals. However, they can be used for any kind of information.
Although most developers these days prefer directing users to a website for further information, being able to have documentation stored locally still makes sense. AmigaGuide documents are normally viewed using AmigaOS' universal viewer, MultiView, but developers can also use the AmigaGuide Library to provide interactive "online help" right from within their applications.
AmigaGuide is a text-based format and can be edited in a text editor quite easily. However, there are dedicated AmigaGuide editors such as GuideMaker or Heddley. You can also find various tools on OS4Depot to help you convert documentation into the AmigaGuide format.
AmigaGuide commands are documented in the SDK (Documentation/AutoDocs/amigaguide_dtc.doc).