If you want the second computer to have the exact same bookmarks as the first, see [[backing up and restoring bookmarks]], just copy the .json file that was backed up to the other computer and use the Choose File option to import it. If you want to add the bookmarks from the first computer to those on the second, first export them to an HTML file and import that HTML file on the other computer. For details see [[Exporting bookmarks to an HTML file]] and [[Importing Bookmarks from an HTML File]]. Another option is to use the [https://addons.mozilla.org/en-US/firefox/addon/10868/ Firefox Sync] add-on to synchronize the bookmarks of the two computers. You need at least Firefox 3.5 for Firefox Sync.