The contents of Web pages are often not self-contained. A page author
often assumes all the readers of the page come through the same path,
and he sometimes omit the information described in the pages on that
path because the readers must already know it. Therefore, indexes
used by search engines based on the contents of each page are also
incomplete. In this paper, we propose a method of discovering those
paths assumed by page authors, and of complementing the incomplete
indexes with keywords extracted from the pages on those paths.