Codex 632 fits comfortably within the genre: while there's little thriller-style action here (no car chases, no gunfights, rarely even a word spoke in anger), there's certainly a great deal of deciphering ancient texts, long expository paragraphs, and jetting around the world to put together the pieces of the puzzle.
In this case, the puzzle is the "true identity" of Christopher Columbus: Portuguese scholar Thomas Noronha is hired by an American historical foundation to complete the research of a recently-expired scholar who they'd contracted with to examine the historical records of the discovery of Brazil, but whose research led him in a much different direction. Noronha must solve the professor's hidden codes and messages in order to uncover just what it was that his predecessor had been on the trail of.
While the family/romantic subplots came off as a bit clumsy, overall this was one of the more intriguing books I've read of the type. Based on an unconventional reading of the historical record, it makes for a fun thought experiment, and quite a decent story.