Dan Brown tries to pass himself of as a historian and his fictionary novel The Da Vinci Code as more than just that, fiction.
It saddens me that so many people will read this novel and accept everything in it as truth just because the author claims to have done extensive research.
First off, the Priory of Sion is crap (see article by real researcher)
http://www.anzwers.org/free/posdebunking/
This sums most of it up (be sure to click though all 4 pages)
http://icq.beliefnet.com/story/135/story_13519_1.html
Didn't even research Da Vinci that well
http://www.newagepointofinfinity.com/new_page_10.htm
Apparently ripped off someone else
http://ideaworx.com/daughter-davinci.html
I will be interested in other peoples comments that have read this book