The Charlemagne Pursuit by Steve Berry. Ballantine Books (2008)
A son's quest for truth, a government cover-up, and an ancient mystery. Intrigued yet? You should be. When Cotton Malone, former U.S. government agent turned rare book dealer, was ten, his father and the submarine he commanded disappeared in the North Atlantic. In The Charlemagne Pursuit, Cotton sets out on a mission to find the truth about his father's death. He soon finds himself entangled in the Charlemagne Pursuit, the search for proof of an unknown ancient civilization on one side and the desire to suppress it on the other. You'll have to read the book to find out how the two are related. While only loosely based on historical fact, I found Berry's imaginative story completely plausible as I was reading. The Charlemagne Pursuit also stands well on its own despite being the fourth book to feature Cotton Malone. Steve Berry is surely compared to Dan Brown on a regular basis, so I hate to do it here, but if you enjoy Brown's work, I'm confident you'll love Berry and Cotton Malone. I enjoyed The Charlemagne Pursuit so much I've gone back to the beginning of the Malone series and have already powered through The Templar Legacy and am well into The Alexandria Link within a matter of days. Both are equal to The Charlemagne Pursuit. So why not start at the beginning?