Using the Index

  To see the index of a book, choose Index from the View menu
  in the Navigation window.  A collapsed view of the index
  appears in the window.

  To expand the entire index, click on the word Index and
  choose Fully Expand from the View menu.

  To expand a part of the index, double click on the right arrow
  next to the letter you want.  The index expands to display the
  top level entries beginning with that letter.  If an index entry
  is preceded by a right arrow, double click again on the right
  arrow to view the sub-entries.

  When you locate the index entry you want, double click on
  the entry to open the Topic window and read that section.

  Note that top level index entries are not hotspots.  You cannot
  double click on them to open a section.  You must first expand
  the top level entry to view the subentries, which are hotspots.