I LOVE this series.
Jean M Auel is not dead, she is working on books 5 and 6 simultaneously and they will be released within a short time of each other - however when that will be, no-one knows!
The best fan site I have found is:
http://www.geocities.com/Athens/6293/auel.html
There is also a really good fan forum at:
http://ecfans.com/forums.htm
The members of this particular forum are very friendly - they have a similar community to the one we have here and they welcome newbies, so I would say it is worth a visit if you are a fan of this series. I post there myself occasionally.
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Time is an illusion. Lunchtime doubly so.
Epona of The Laughing Hyenas