If the page no longer exists you have probably lost the information, unless you deliberatly saved the webpage (yourself manually; by working 'offline', or some sort of archive extension) to your computer. That is something you need to do if you expect a webpage to change. Your bookmarks or history only point you back at the webpage, they are not the information from that webpage. There are two possibilities you could try '''but''' this only works for any original material, not anything you edited yourself. * '''Offline''' if you use '''file -> work offline ''' . Then if you try the URL you have whilst offline, if firefox does have a cached copy it may load. * '''Web Cache''', some pages get archived elsewhere on the web, google for instance stores current or sometimes older versions of sites as a cache copy, look for the item on google and if you see an alternative link marked 'cached' &/or 'Similar' try clicking on them. If you are lucky and find the information remember to immediately use File -> save page as , and make a copy for your computer.