Works in FF5, too Rated 5 out of 5 stars
Changing the version number in the install.rdf file as described in tmtisfree's (and others') instructions below still works fine for me in the Mac version of FF5. (See https://addons.mozilla.org/en-US/firefox/addon/openbook/reviews/273168/ for details. ) I'm thrilled that I can still use this add-on! I hate FF's Add Bookmark dialog box as it is — which is why I'm giving OpenBook five stars even though it hasn't been updated for quite a while.This user has a previous review of this add-on.