The Guide evolved from the need to have an application that could organize information and ideas in a hierarchical, tree-like structure. Tree-based structures are frequently employed to manage information through a "divide-and-conquer" approach, wherein each level of the tree represents a further level of specialization of the parent-level topic — the best example of this being a book.
The Guide is an application that allows you create documents ("guides") which inherently have a tree (which you can modify as you please) and text associated with each node of the tree. The text itself is of the rich-text variety, and the editor allows you to modify the style and formatting of the text (fonts, bold, italics etc).
For the initiated, the Guide is a two-pane extrinsic outliner. This concept is similar to mindmapping in some ways.
A picture is worth a thousand words: have a look at some screenshots.
Operating System : 32-bit MS Windows (NT/2000/XP)
Free, Open Source: The Guide