These are just some of the books which were used as source for Da Vinci Code. Not a word is Dan Brown's original, and Da Vinci Code is just, tip of the ice berg. Enjoy Reading!!!
1) Holy Blood and Holy Grail - published in 1982
2) Templar Revelation - published 11 years before.
3) The Messianic Legacy - The equally startling sequel to 'The Holy Blood and Holy Grail' by the same authors.
4) Dead Sea Scrolls Deception - by Michael Baigent, Richard Leigh
Also Read
5) The Jesus Papers, Exposing History's Greatest Coverup - by Michael Baigent
6) Gnostic Gospels - by Elaine Pagels
7) The Gospel of Judas.
8) Turin Shroud: in whose image ( By 'Templar Revelation' Authors )