Books similar to Dan Brown's Da Vinci Code
Can anyone name any fiction books that are similar to the book The Da Vinci Code. I am buying some books for a relative's birthday and they really liked this book, so anything around it would be fabulous.
I've already got The Amber Room, The Last Templar, The Assassini, The Genesis Code, and Overseer to look at in the shops.
Anymore? and should I stay away from any of the ones I mentioned.
I don't want books that are terribly hard to follow because the person isn't a big reader and can easily lose his way if too much.
Thank you.