Abstract: Caching is a widely used technology on the Web, particularly by search engines which follow hyperlinks and generate indexes and directories of Web pages and their contents. Indeed, some search engines allow users to view pages as they were last retrieved by the search engine. Whether a given page exits in the cache or not, however, is completely arbitrary, and so is the time of its retrieval. The ‘Web page cache-on-demand’ process allows Web users to decide exactly when a given Web page should be retrieved and cached, thereby significantly improving Web users' ability to document Web contents.