A few of the library's books are designed as unframed documents. These unframed books have varying navigational aids; some have only hot-linked words and others have graphical button bars throughout the text. As shown here, there are two different kinds of button bars.
Buttons work slightly differently in the two kinds of bars:

	Full Button Bars	Varying Button Bars
	Goes to the Table of Contents.	Goes to the Table of Contents.
	Goes to the beginning of the current chapter or, if you are at the beginning of a chapter, to the previous chapter.	Goes to the title and copyright information at the beginning of the book.
	Goes to the beginning of the previous section.	Goes to the beginning of the current chapter or, if you are at the beginning of a chapter, to the previous chapter.
	Goes to the beginning of the next section.	Goes to the beginning of the next chapter.
	Goes to the beginning of the next chapter.	(Does not appear.)
	Goes to the Index.	Goes to the Index.
	Opens the help window.	(Does not appear.)