Archangel.

As I read The Da Vinci Code, I can't help but think of another book.

Archangel by Robert Harris.

Fans of the Da Vinci Code, and History should read this. The latter was published in 1999. Its plot bears a stark resemblance - the old man died with his secrets, the academic trying to uncover them in time, with the police monitoring him closely.

Archangel is more deep, absorbing, and has a flowing storyline; In comparison, Da Vinci is very dynamic, with surprises at every corner. However the Da Vinci Code is very educational too - I had no idea what the Fibbonacci sequence? was prior to reading. Archangel makes a good candidate for History students interested about Russia during Stalin's rule.

Here's a gist of the book:
http://www.randomhouse.co.uk/features/harris/

I can't say Archangel is a better book than Da Vinci, because I'm not done with the latter yet.