GnomeDruid — Widget for sequentially stepping through some pages.
GnomeDruidPage — A widget representing a single page inside a druid.
GnomeDruidPageEdge — A widget used to implement first and last pages in a druid's sequence.
GnomeDruidPageStandard — A widget used to implement the middle pages in a druid's sequence.

Druids (sometimes called Wizards on other systems) are a series of dialog boxes that lead the user through a task that is serial in nature (that is, it has a natural beginning, sequence through the pages and an end).

Some applications (for example GNOME Lokkit -- for setting up simple firewall settings) are purely a series of screens that extract some information from the user and then performs an action based on that data. Other applications may be more traditional in nature, however they may wish to run the user through a series of question the first time they run the application; such as to set things up correctly or to import settings from another program. Both these types of programs can use the various druid functions to make their implementation easier.