Learn by screencast.
You can use it to display available API documentation (extracted from class/method comments) and to provide custom documentation in form of simple written text books. These informations are extracted from the image by two predefined help builder classes that convert the help contents to instances of "HelpTopic". These HelpTopics can be nested (book structure) and displayed in a HelpBrowser. Since help text is extracted/stored in classes and methods you can use the usual tools to maintain and package help contents together with your code.
The design is simple but nonetheless powerful since by allowing you to integrate own custom help builder classes you can easily integrate documentation extracted from any source available to you.