The following page: http://support.mozilla.com/en-US/kb/Blocking%20cookies?s=blocking+cookies&as=s is incomplete - please see as example: "Viewing a list of blocked sites To see a list of sites that you have blocked from setting cookies: " There is no text after the colon. Also the same page refers to selecting a "Tools" menu from the Firefox window(whatever that is?) - in order to get "Page info" so that cookies can be blocked. I can't the Tools menu - clicking on the Firefox (at top left hand of page) does not give this option. I was looking at this page in order to find out how to permanently block specific cookie sites. I block them when they appear when I have set "accept 3rd party cookes to "keep until" - "ask me every time" - and I also have "clear history when Firefox closes" set. However the blocked addresses are deleted when I come out of Firefox - this is very irritating as there are some cookies I wish to permanently block. This means that every time I open a web site I have to click on "deny" cookie several times - even thought they are the same ones I have blocked in a differenrt session. I prefer to choose what I block as some sites really don't work without their personal cookies - usually to support subscriber log in (e.g to log in to the "New Scientist" site)so "private browsing" doesn't really help and as you have mentioned elsewhere blocking 3rd party cookies can also cause problems yours H.Ruddy Thank you for "Do Not Track" it's a good start although it will have no effect if the sites ignore it.