The Help window Search menu contains the following
  items:

  -  History...

     Displays a list of help topics you have already seen
     and lets you perform a Go To or Visit operation on
     any of them.

  -  Title...

     Displays a list of all the available help topic
     titles and allows you to perform a Go To or Visit
     operation on visit any of them. You can also enter a
     word or phrase, and only those topics that contain
     it are displayed.

  -  Keyword...

     Displays a list of help keywords and allows you to
     select any of them. All topics having that keyword
     are displayed, and you can then perform a Go To or
     Visit operation on any of them.

  For more information, choose the menu item from the
  list of additional topics below.